Pyrrolo - dipyridine compounds

ABSTRACT

In one aspect, the invention provides compounds of Formula I Formula Ia, Formula Ib, Formula Ic, and Formula Id and salts, hydrates and isomers thereof. In another aspect, the invention provides a method of promoting bone formation in a subject in need thereof by administering to the subject a therapeutically effective amount of a compound of Formula I, Formula Ia, Formula Ib, Formula Ic, or Formula Id. The present invention also provides orthopedic and periodontal devices, as well as methods for the treatment of renal disease, diabetes bone loss, and cancer, using a compound of Formula I, Formula Ia, Formula Ib, Formula Ic, or Formula Id.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application claims the benefit of priority under 35 U.S.C. § 119(e)to U.S. Provisional Application Ser. No. 62/718,612 filed Aug. 14, 2018,the disclosure of which is incorporated herein by reference in itsentirety.

STATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSOREDRESEARCH AND DEVELOPMENT

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REFERENCE TO A “SEQUENCE LISTING,” A TABLE, OR A COMPUTER PROGRAMLISTING APPENDIX SUBMITTED ON A COMPACT DISK

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BACKGROUND OF THE INVENTION

Bone homeostasis involves the counterbalancing processes of boneformation and bone resorption. Increased bone resorption and loss ofbone homeostasis is associated with a number of diseases and disorders,such as osteoporosis and Paget's disease. All FDA approved therapeuticsfor treating low bone density, except Teriparatide, do so by stoppingbone resorption, hence antiresoptives. Antiresorptives act on theosteoclast cell by stopping them from resorbing the bone.

It is well known in the art that bone can be formed by two processes;one of which is mediated though a chondrocyte cartilage intermediate,(endochondral) and the other is a direct process that stimulates theosteoblast cells (intramembranous). The endochondral process involveschondrocytes/cartilage cells which die and leave a void space whichbecome occupied by osteoblast cells that calcified on the surface of thechondrocyte cartilage calcification. During the resorption process theosteoclasts resorb this cartilage calcification leaving a cleannon-cartilage bone mineral behind. The endochondral process is presentduring the rudimentary formation and growth of long bones, and duringthe cartilage callus process of bone fractures. Endochondral processbegins when mesenchymal stem cells differentiate into chondrocytescreating cartilage. Whereas the intramembranous process occurs duringnew bone growth stage of bone fractures and formation of bones of thehead. Intramembranous process occurs when mesenchymal stem cellsdifferentiate into an osteoblast cell. Unlike cartilage, which is anelastic tissue, bone is hard and rigid. Two very different cellularprocesses (osteoblasts vs chondrocytes) involving different molecular(WNT vs BMP) and cellular mechanisms (osteoblasts vs chondrocytes).

It is well understood that osteoblast cells are responsible forsecreting the bone mineral that causes increases in bone density. Todate, only teriparatide was known to stimulate the osteoblast cell toincrease mineral deposit, albeit indirectly through the Wnt pathway.

It is desirable to cause osteoblast mineral deposition (bone formation)for treatment of a wide variety of disparate disorders in mammalsincluding simple aging, bone degeneration and osteoporosis, fracturehealing, osteogenesis imperfecta, HPP, fusion of two bones orarthrodesis across a joint, any low bone density disorder, etc., as wellas for successful installation of various medical orthopedic andperiodontal implants such as screws, rods, titanium cage for spinalfusion, hip joints, knee joint, ankle joints, shoulder joints, dentalimplants, bone grafts, plates and rods, etc.

The use of antiresorptives such as, but not limited to; Cathepsin Kinhibitors, Rank Ligand inhibitor, Denosumab, Prolia, an osteoprotegerin(OPG) inhibitor, alendronate, selective estrogen receptor modulators(SERMs), bisphosphonates, and the like for treating a subject with lowbone density conditions has resulted, at least in part, with a verysmall initial increased bone mineral deposition of less than 6% in thefirst yearfollowed by smaller gains in subsequent years. The overallgain in bone density from an antiresorptive therapy (stopping bone loss)has been reported at 9.4% over three years. Such treatable conditionsmay include osteopenia, osteoporosis, arthritis, tumor metastases,osteogenesis imperfecta, Paget's disease, secondary low bone densitydisorders/diseases and other metabolic bone disorders.

The use of Parathyroid hormone and analogs, Prostaglandin agonists,PDGE2, PDGE, Forteo, osteoprotegerin (OPG) inhibitor, teriparatide,BMP2, BMP7, BMP4, EP4 agonist and the like may be used for causing adesirable increase bone mineral in a subject with low bone densityconditions. Such conditions may include osteopenia, osteoporosis,arthritis, tumor metastases, osteogenesis imperfecta, Paget's disease,secondary low bone density disorders, bone fusion, spinal fusion,arthrodesis and other metabolic bone disorders. However, the use of BMPagonists for treating systemic disease has not been pursued past an FDAPhase I Clinical Trial.

Additionally, it is known in the art the use of PTH, TGFP bindingproteins and like for increasing bone mineralization to treat conditionswhich may be characterized in part by increased fracture risk, such asosteopenia, degenerative disk disease, bone fractures, osteoporosis,arthritis, tumor metastases, osteogenesis imperfecta, Paget's disease,and other metabolic bone disorders Demineralized bone matrix is alsoknown to be able to be partially conducive to small amount of new bonegrowth, due the endogenous growth factors (TGFβ binding proteins (BMPs))surviving the sterilization procedure of the cadaver bone. However,demineralized bone matrix is generally sourced from donor cadaver banksand carries certain risks such as disease transmission or bacterialcontamination. Other versions of demineralized bone matrix are moreheavily processed and carry less disease risk. A current unmet medicalneed using current approved therapies in the field of non-unionfractures is the desire to improve the poor healing observed in longbone large defects consisting of large voids between bone fracture ends.The use of demineralized bone or similar osteoconductive material, whichis known in the art, has not resulted in the desired effects of fusinglong bones.

Thus, there remains a need in the art for new methods of treating bonedisorders, bone fractures and related issues. The present inventionmeets these and other needs.

BRIEF SUMMARY OF THE INVENTION

In one aspect, the present invention provides compounds andcompositions, as well as methods of using such compounds andcompositions. In a first embodiment, the present invention providescompounds of Formula I:

or a salt, hydrate, prodrug, or isomer thereof, wherein

X is selected from CR^(3b) and N, wherein N is optionally oxidized tothe corresponding N-oxide;

Y is selected from CR^(3c) and N, wherein N is optionally oxidized tothe corresponding N-oxide;

Z is selected from CR^(3d) and N, wherein N is optionally oxidized tothe corresponding N-oxide,

provided that at least one of X, Y, and Z is N or the correspondingN-oxide;

A is

R^(N) is selected from the group consisting of heterocyclyl andheteroaryl, wherein

the heterocyclyl moiety is selected from monocyclic, fused bicyclic, andbridged cyclic, the monocyclic heterocyclyl comprising from 4 to 7 ringmembers, the fused bicyclic and bridged bicyclic heterocyclyl comprisingfrom 7 to 10 ring members, each heterocyclyl moiety having from 1 to 3heteroatoms as ring members selected from N, O, and S, wherein eachheterocyclyl moiety comprises at least one nitrogen atom as a ringmember and is optionally substituted with from 1 to 3R⁶ moieties,

the heteroaryl moiety comprises from 5 to 10 ring members, wherein atleast one ring member is a nitrogen atom and is optionally substitutedwith from 1 to 3R⁶ moieties,

each R², R^(3b), R^(3c) and R^(3d) is independently selected from thegroup consisting of H, halogen, C₁₋₆ alkyl, C₁₋₆ haloalkyl, C₂₋₆alkenyl, C₂₋₆ alkynyl, C₁₋₆ alkoxy, C₁₋₆ haloalkoxy, C₁₋₆ alkyl-OH,—O—C₁₋₆ alkyl-OH, C₃₋₆ cycloalkyl-C₁₋₄alkoxy, and —OH; and

R⁶ is selected from the group consisting of —OH, C₁₋₃ alkyl, C₁₋₃alkyl-OH, —O—C₁₋₃ alkyl, C₃₋₄ heteroalkyl, C₁₋₃ haloalkyl, —O—C₁₋₃haloalkyl, halogen, and oxo.

In a second embodiment, the present invention provides a method ofpromoting bone formation and fusion in a subject in need thereof. Themethod includes administering to the subject a therapeutically effectiveamount of a compound of Formula I, Formula Ia, Formula Ib, Formula Ic,or Formula Id as described herein, thereby promoting bone formation inthe subject. Bone formation can be systemic or local. For local boneformation, in some embodiments the compound may be administered with anosteoconductive agent, e.g., an osteoconductive matrix.

In a third embodiment, the present invention provides a method oftreating renal damage. The method includes administering to a subject inneed thereof, a therapeutically effective amount of a compound ofFormula I, Formula Ia, Formula Ib, Formula Ic, or Formula Id.

In a fourth embodiment, the present invention provides a method oftreating diabetes. The method includes administering to a subject inneed thereof, a therapeutically effective amount of a compound ofFormula I, Formula Ia, Formula Ib, Formula Ic, or Formula Id.

In a fifth embodiment, the present invention provides a method oftreating cancer. The method includes administering to a subject in needthereof, a therapeutically effective amount of a compound of Formula I,Formula Ia, Formula Ib, Formula Ic, or Formula Id.

In a sixth embodiment, the present invention provides a medical device,e.g., an orthopedic or periodontal medical device. The device includes astructural support, wherein an implantable portion of the structuralsupport is adapted to be permanently implanted within a subject. Theimplantable portion is attached to a bone, and the structural supportbears at least a partial external coating including a compound ofFormula I, Formula Ia, Formula Ib, Formula Ic, or Formula Id.

In a seventh embodiment, the present invention provides compounds orcompositions as described herein (e.g., a compound or composition ofFormula I, Formula Ia, or Formula Ib, Formula Ic, or Formula Id) for usein the preparation of a medicament for the treatment of a disease orcondition as described herein. In some embodiments, the disease orcondition is injured bone, bone fracture, weakened bone, osteogenesisimperfecta, hypophosphatasia (HPP), osteopenia, osteoporosis,arthrodesis or a condition characterized by low bone mass or density.Also contemplated herein is the use of the compounds or compositionsdescribed herein in periodontal implants or medical orthopedic implants.Orthopedic implants include screws, rods, as well as titanium cages forus in, for example, spinal fusion.

In an eighth embodiment, the present invention provides a orthobiologic,e.g., a bone formation inducer for surgical implantation with or withouta bone graft device. The device includes a structural support, whereinan implantable portion of the structural support is adapted to bepermanently implanted within a subject. The implantable portion isattached to a bone, and the structural support bears at least a partialexternal coating including a compound of Formula I, Formula Ia, FormulaIb, Formula Ic, or Formula Id.

In a ninth embodiment, the present invention provides a method oftreating bone loss. The method includes administering to a subject inneed thereof, a therapeutically effective amount of a compound ofFormula I, Formula Ia, Formula Ib, Formula Ic, or Formula Id in seriesor in combination with an antiresorptive agent.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1: Bone mass homeostasis is regulated by the coupled process ofbone formation (increasing the amount of bone mineral deposit) and theprocess of bone resorption (decreasing the amount of bone mineraldeposit). Bone formation can be positively promoted by activities andagents that act on the osteoblast bone-forming cell, such as exercise,and indirectly by PTH (teriparatide), or by sclerostin inhibitors suchas the compounds of the present invention. Bone resorption can beinhibited by antiresorptive agents such as RankL inhibitor, selectiveestrogen receptor modulator (SERM), calcium, estrogen, alendronate,fosamax, denosumab, prolia, cathepsin K modulators, bisphosphonates,calcitonin, and other agents acting to stop the activity of theosteoclast cell.

DETAILED DESCRIPTION OF THE INVENTION I. INTRODUCTION

Bone mass homeostasis and bone remodeling involve the counterbalancingprocesses of bone formation (osteoblast cell depositing mineral, ananabolic process) and bone resorption (osteoclast cell resorbingmineral, bone loss, a catabolic process). These two processes arecoupled in a healthy bone. See, FIG. 1. In bone formation, osteoblastssynthesize bone matrix and regulate mineralization, and then terminallydifferentiate into osteocytes or bone lining cells. In bone resorption,a different cell type—osteoclasts—remove mineralized bone matrix andbreak up the organic bone to release calcium in the serum. See, e.g.,Kular et al., Clinical Biochemistry 45:863-873 (2012).

The osteoblasts (bone formation cells) and osteoclasts (bone resorptioncells) are regulated by different mechanisms. Osteoclast celldifferentiation is regulated or controlled by the osteoblast (Glass etal., Dev Cell 8:751-764 (2005)) or other hormones like PTH, calcitonin,or IL6. In contrast, osteoblast cell differentiation or activity is notregulated or controlled by osteoclast cells, but rather are controlledby different signals, like CPFA, hedgehog, WNT/LRP, and sclerostin. Boneformation can occur via endochondral ossificiation or intramembranousossification (sclerostin). In intramembranous ossification, bone formsdirectly through the stimulation of osteoblast/osteocyte bone cells. Inendochondral ossification, bone formation occurs by way of a cartilagetemplate, which increases the amount of time that it takes bone to form.BMP signaling is implicated in endochondral ossification, whereas Wntsignaling has been shown to be involved in both endochondral andintramembranous ossification.

Under normal healthy conditions, bone remodeling (or bone homeostasis)involves the degradation of old bone (via osteoclast cells) and therepair or replacement of the old bone with new bone (via osteoblastcells). When this homeostasis is disrupted and bone resorption exceedsbone formation, i.e. diseased bone state, the results uncouple boneresorption from bone formation. Increased bone resorption leads todecreased bone mass (loss of trabecular bone) and greater bone fragility(less bone strength). A number of diseases and conditions are associatedwith increased bone resorption, including osteoporosis, osteogenesisimperfecta, Paget's disease of bone, metabolic bone disease, bonechanges secondary to cancer, and other diseases characterized orassociated with low bone density.

Diseases caused by increased bone resorption are associated withdecreased bone mass and greater bone fragility and are frequentlytreated with antiresorptive agents such as bisphosphonates, denosumab,prolia, alendronate, cathepsin K modulators, RankL inhibitors,estrogens, cathepsin K inhibitors, and selective estrogen receptormodulators, to name but a few. These agents function by preventing orinhibiting osteoclast cell bone resorption, either directly orindirectly. See, FIG. 1. However, these agents do not promote theformation of new bone by the osteoblast cell (i.e., anabolic boneformation); in contrast, administration of one dose of an anabolic agentnormally results in the an annual cumulative increase of >8% frombaseline in bone formation in lumbar vertebra of humans). Administrationof an antiresorptive does result in a modest increase in bone densitythe first year of <7% but thereafter the increase in bone density is<3.5% with an annual cumulative increase of <10%. Therefore, although afragile osteoporotic bone that is treated with an antiresorptive agentwill result in the fragile bone not getting more fragile, the fragilebone will not be stronger or have increased strength because theantiresorptive agent does not promote new bone growth by depositing morebone mineral to increase bone density. In contrast, an agent thatpromotes anabolic bone growth, for example, by stimulating the activityof osteoblasts, promotes the deposition of more bone matrix, or ifproliferation were stimulated, the agent would result in more osteoblastcells, thus resulting in more bone cells to bridge a gap to fuse twobones. Thus, a fragile osteoporotic bone treated with an anabolic boneformation agent will allow the bone not to get more fragile, and alsowill allow the bone to have more strength due to increased boneformation.

With reference to FIG. 1, and without being bound to a particulartheory, if one thinks of the bone as a bathtub, the drain is reminiscentof bone loss or resorption and the faucet reminiscent of the bone beingadded or bone formation. Both the faucet and drain are adding andremoving at the same rate (coupled) until one ages or a disease strikescausing either the faucet to be turned down or the drain to be increasedin size. Perturbations such as these result in an imbalance (uncoupling)of formation/resorption causing bone density to become lowered. Forexample, imagine a sponge that has an outer core and on the inside ismade of fibers stretching from one end to the other. During boneresorption these fibers are removed, and if bone resorption is occurringat a rate faster than bone building or formation then these fibers wouldbe few and the bone would become fragile. It would not take muchstrength to break a sponge with few inside fibers versus one with manyinside fibers. Because the process of bone resorption is wellunderstood, many of the marketed therapeutics stop bone resorption byacting on the osteoclast cells. These include antiresorptive agents suchas Cathepsin K inhibitors, Rank Ligand inhibitor, Denosumab, Prolia,Fosamax, Evista, Premarin, osteoprotegerin (OPG) inhibitors,alendronate, selective estrogen receptor modulators (SERMs),bisphosphonates, and other agents acting to stop the activity of theosteoclast cell.

While still considering the analogy of the sponge, to increase bonestrength, the number of fibers on the inside of the bone to increasebone strength. However, is not possible to increase bone strength byacting on the bone resorbing cell, the osteoclast. Thus, one needs tofocus on the bone forming osteoblast cell. Unlike bone resorption, boneformation is not well understood and, until recently, only one systemictherapeutic (teriparatide) and one surgical implant (Infuse with BMPprotein) has been marketed to promote bone formation. However, BMPproduct acts to increase chondrocytes and promote cartilage production.This process sometimes leads to the chondrocytes then being replaced byosteoblasts.

Intermittent teriparatide administration increases bone densitysystemically by activation of PKA which then phosphorylates LRP andactivates the WNT pathway (Wan et al., Genes Dev. 22(21): 2968-2979(2008)). This increase in bone density occurs along already laid downtrabeculae within the bone matrix. The osteoblast cells lining thetrabeculae secrete mineral unto the existing trabecular bone thusincreasing the amount of mineral and density of the trabeculae.

When a bone void exists whereby a large segment of bone is removedcausing non-union of the bone or a critical size defect. The bone isunable to heal itself across a large gap. The addition of BMP to thesite causes the pluripotent cells to differentiate intochondrocytes/cartilage and produce a cartilage callus. The ability ofthe gap to be filled by bone instead of cartilage would requireosteoblast bone cells to undergo proliferation to fill the gap and thento deposit mineral to fill the void.

Without being bound to a particular theory, it is believed thatcompounds of the present invention are SOST (Sclerostin) and/or WISEantagonists that function by modulating the Wnt/LRP and/or BMP signalingpathways. SOST and WISE are proteins that are believed to modulate boneformation by either binding to the Wnt co-receptor LRP, therebyinhibiting the Wnt signaling pathway, or by binding to BMP andinhibiting BMP activity, via different amino acid sequences or domains.By neutralizing the inhibitory effects of SOST and/or WISE proteins onthe Wnt pathway, the compounds and compositions of the present inventionrestore Wnt signaling and promote bone formation/growth. Thus, in oneaspect, the present invention provides compounds, compositions, andmethods for promoting bone formation in a subject. The bone formationcan be systemic or local. The compounds and compositions of the presentinvention can be administered locally and/or systemically and optionallycan be administered sequentially or in combination with one or moreother therapeutic agents. In another aspect, the present inventionprovides implantable devices as structural scaffolds for allowingosteoblast/osteocytes to migrate into the scaffold and deposit bonemineral and also for delivering the compounds and compositions of thepresent invention, e.g., for promoting bone formation at the site ofimplantation. In another aspect, the compounds and compositions of thepresent invention can be used to treat renal damage, diabetes, boneloss, and cancer.

II. DEFINITIONS

As used herein, the term “pharmaceutically acceptable excipient” refersto a substance that aids the administration of an active agent to andabsorption by a subject. Pharmaceutically acceptable excipients usefulin the present invention include, but are not limited to, binders,fillers, disintegrants, lubricants, coatings, sweeteners, flavors andcolors. One of skill in the art will recognize that other pharmaceuticalexcipients are useful in the present invention.

As used herein, the term “alkyl” refers to a straight or branched,saturated, aliphatic radical having the number of carbon atomsindicated. For example, C₁-C₆ alkyl (or C₁₋₆ alkyl) includes, but is notlimited to, methyl, ethyl, propyl, butyl, pentyl, hexyl, iso-propyl,iso-butyl, sec-butyl, tert-butyl, etc.

Alkylene represents either straight chain or branched alkylene of 1 to 7carbon atoms, i.e. a divalent hydrocarbon radical of 1 to 7 carbonatoms; for instance, straight chain alkylene being the bivalent radicalof Formula —(CH₂)_(n)—, where n is 1, 2, 3, 4, 5, 6 or 7. Preferablyalkylene represents straight chain alkylene of 1 to 4 carbon atoms, e.g.a methylene, ethylene, propylene or butylene chain, or the methylene,ethylene, propylene or butylene chain mono-substituted by C₁-C₃-alkyl(preferably methyl) or disubstituted on the same or different carbonatoms by C₁-C₃-alkyl (preferably methyl), the total number of carbonatoms being up to and including 7. One of skill in the art willappreciate that a single carbon of the alkylene can be divalent, such asin —CH((CH₂)_(n)CH₃)—, wherein n=0-5.

As used herein, the term “alkoxy” or “—O-alkyl” refers to alkyl with theinclusion of an oxygen atom, for example, methoxy, ethoxy, etc.“Haloalkoxy” is as defined for alkoxy where some or all of the hydrogenatoms are substituted with halogen atoms. For example,halo-substituted-alkoxy includes trifluoromethoxy, etc.

The term “hydroxyalkyl” or “alkyl-OH” refers to an alkyl group, asdefined above, where at least one of the hydrogen atoms is replaced witha hydroxy group. As for the alkyl group, hydroxyalkyl groups can haveany suitable number of carbon atoms, such as C₁₋₆. Exemplaryhydroxyalkyl groups include, but are not limited to, hydroxy-methyl,hydroxyethyl (where the hydroxy is in the 1- or 2-position),hydroxypropyl (where the hydroxy is in the 1-, 2- or 3-position), etc.

As used herein, the term “alkenyl” refers to either a straight chain orbranched hydrocarbon of 2 to 6 carbon atoms, having at least one doublebond. Examples of alkenyl groups include, but are not limited to, vinyl,propenyl, isopropenyl, butenyl, isobutenyl, butadienyl, pentenyl orhexadienyl.

As used herein, the term “alkynyl” refers to either a straight chain orbranched hydrocarbon of 2 to 6 carbon atoms, having at least one triplebond. Examples of alkynyl groups include, but are not limited to,acetylenyl, propynyl or butynyl.

As used herein, the term “halogen” refers to fluorine, chlorine, bromineand iodine.

As used herein, the term “haloalkyl” refers to alkyl as defined abovewhere some or all of the hydrogen atoms are substituted with halogenatoms. Halogen (halo) preferably represents chloro or fluoro, but mayalso be bromo or iodo. For example, haloalkyl includes trifluoromethyl,fluoromethyl, etc. The term “perfluoro” defines a compound or radicalwhich has at least two available hydrogens substituted with fluorine.For example, perfluoromethane refers to 1,1,1-trifluoromethyl, andperfluoromethoxy refers to 1,1,1-trifluoromethoxy.

As used herein, the term “heteroalkyl” refers to an alkyl group havingfrom 1 to 3 heteroatoms such as N, O and S. Heteroalkyl groups have theindicated number of carbon atoms where at least one non-terminal carbonis replaced with a heteroatom. Additional heteroatoms can also beuseful, including, but not limited to, B, Al, Si and P. The heteroatomscan also be oxidized, such as, but not limited to, —S(O)— and —S(O)₂—.For example, heteroalkyl can include ethers, thioethers andalkyl-amines. Heteroalkyl groups do not include peroxides (—O—O—) orother consecutively linked heteroatoms.

As used herein, the term “oxo” refers to a double bonded oxygen (═O).

As used herein, the term “cycloalkyl” refers to a saturated or partiallyunsaturated, monocyclic, fused bicyclic or bridged polycyclic ringassembly containing from 3 to 12 ring atoms, 3 to 8, 3 to 6, or thenumber of atoms indicated. For example, C₃₋₈ cycloalkyl includescyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and up to cyclooctyl.The cycloalkyl groups of the present invention are optionallysubstituted as defined below.

As used herein, the terms “heterocycle,” “heterocycloalkyl,” and“heterocyclyl” refer to a ring system having from 3 ring members toabout 20 ring members and from 1 to about 5 heteroatoms such as N, O andS. Additional heteroatoms can also be useful, including, but not limitedto, B, Al, Si and P. The heteroatoms can also be oxidized, such as, butnot limited to, —S(O)— and —S(O)₂—. The term heterocycle includesmonocyclic, fused bicyclic, and bridged cyclic moieties. For example,heterocycle includes, but is not limited to, tetrahydrofuranyl,tetrahydrothiophenyl, morpholino, pyrrolidinyl, pyrrolinyl,imidazolidinyl, imidazolinyl, pyrazolidinyl, pyrazolinyl, piperazinyl,piperidinyl, indolinyl, quinuclidinyl hexahydro-1H-furo[3,4-c]pyrrolyland 1,4-dioxa-8-aza-spiro[4.5]dec-8-yl. The heterocycloalkyl groups ofthe present invention are optionally substituted as defined below.

Substituents for the cycloalkyl and heterocyclyl groups are varied andare independently selected from: -halogen, C₁₋₈alkyl, —OR′, —OC(O)R′,—NR′R″, —SR′, —R′, —CN, —NO₂, —CO₂R′, —CONR′R″, —C(O)R′, —OC(O)NR′R″,—NR″C(O)R′, —NR″C(O)₂R′, —NR′—C(O)N R″R′″, —S(O)R′, —S(O)₂R′,—S(O)₂NR′R″, perfluoro(C₁-C₄)alkoxy, and perfluoro(C₁-C₄)alkyl, in anumber ranging from zero to the total number of open valences on thering system; and where R′, R″ and R′″ are independently selected fromhydrogen, (C₁-C₈)alkyl and C₃₋₈ heteroalkyl, and phenyl.

As used herein, a group “linked via a carbon atom” refers to a linkagebetween a carbon atom of the referenced group and the rest of themolecule. A group “linked via a nitrogen atom” refers to a linkagebetween a nitrogen atom of the referenced group and the rest of themolecule. By way of example only, a heterocyclyl group linked via acarbon atom may be:

where the wavy line indicates the point of attachment to the rest of themolecule. By way of example only, a heterocyclyl group linked via anitrogen atom may be:

where the wavy line indicates the point of attachment to the rest of themolecule.

As used herein, where a referenced compound is an N-oxide, it comprisesan N—O bond with three additional bonds to the nitrogen, i.e., anN-oxide refers to a group R₃N⁺—O⁻. By way of example only, N-oxides mayinclude:

and the like.

As used herein, the term “aryl” refers to a monocyclic or fusedbicyclic, tricyclic or greater, aromatic ring assembly containing 6 to16 ring carbon atoms. For example, aryl may be phenyl, benzyl ornaphthyl, preferably phenyl. “Arylene” means a divalent radical derivedfrom an aryl group. Aryl groups can be mono-, di- or tri-substituted byone, two or three radicals as described below.

Substituents for the aryl groups are varied and are selected from:-halogen, —OR′, —OC(O)R′, —NR′R″, —SR′, —R′, —CN, —NO₂, —CO₂R′,—CONR′R″, —C(O)R′, —OC(O)NR′R″, —NR″C(O)R′, —NR″C(O)₂R′,—NR′—C(O)NR″R′″, —NH—C(NH₂)═NH, —NR′C(NH₂)═NH, —NH—C(NH₂)═NR′, —S(O)R′,—S(O)₂R′, —S(O)₂NR′R″, alkylenedioxy, heteroaryl,—C₁₋₂alkylene-heteroaryl, heterocyclyl, C₁₋₂alkylene-heterocyclyl,phenyl, perfluoro(C₁-C₄)alkoxy, and perfluoro(C₁-C₄)alkyl, in a numberranging from zero to the total number of open valences on the aromaticring system; and where R′, R″ and R′″ are independently selected fromhydrogen, (C₁-C₈)alkyl and C₃₋₈ heteroalkyl, and phenyl. Alkylenedioxyis a divalent substitute attached to two adjacent carbon atoms ofphenyl, e.g. methylenedioxy or ethylenedioxy. Oxy-C₂-C₃-alkylene is alsoa divalent substituent attached to two adjacent carbon atoms of phenyl,e.g. oxyethylene or oxypropylene.

Examples of substituted phenyl groups include, but are not limited to4-chlorophen-1-yl, 3,4-dichlorophen-1-yl, 4-methoxyphen-1-yl,4-methylphen-1-yl, 4-aminomethylphen-1-yl,4-methoxyethylaminomethylphen-1-yl, 4-hydroxyethylaminomethylphen-1-yl,4-hydroxyethyl-(methyl)-aminomethylphen-1-yl, 3-aminomethylphen-1-yl,4-N-acetylaminomethylphen-1-yl, 4-aminophen-1-yl, 3-aminophen-1-yl,2-aminophen-1-yl, 4-phenyl-phen-1-yl, 4-(imidazol-1-yl)-phen-yl,4-(imidazol-1-ylmethyl)-phen-1-yl, 4-(morpholin-1-yl)-phen-1-yl,4-(morpholin-1-ylmethyl)-phen-1-yl,4-(2-methoxyethylaminomethyl)-phen-1-yl and4-(pyrrolidin-1-ylmethyl)-phen-1-yl, 4-(thiophenyl)-phen-1-yl,4-(3-thiophenyl)-phen-1-yl, 4-(4-methylpiperazin-1-yl)-phen-1-yl, and4-(piperidinyl)-phenyl and 4-(pyridinyl)-phenyl optionally substitutedin the heterocyclic or heteroaryl ring.

As used herein, the term “heteroaryl” refers to a monocyclic or fusedbicyclic or tricyclic aromatic ring assembly containing 5 to 16 ringatoms, where from 1 to 4 of the ring atoms are a heteroatom each N, O orS. For example, heteroaryl includes pyridyl, indolyl, indazolyl,quinoxalinyl, quinolinyl, isoquinolinyl, benzothienyl, benzofuranyl,furanyl, pyrrolyl, thiazolyl, benzothiazolyl, oxazolyl, isoxazolyl,triazolyl, tetrazolyl, pyrazolyl, imidazolyl, thienyl, or any otherradicals substituted, especially mono- or di-substituted, by e.g. alkyl,nitro or halogen. Pyridyl represents 2-, 3- or 4-pyridyl. Thienylrepresents 2- or 3-thienyl. Quinolinyl represents preferably 2-, 3- or4-quinolinyl. Isoquinolinyl represents preferably 1-, 3- or4-isoquinolinyl. Benzopyranyl, benzothiopyranyl represents preferably3-benzopyranyl or 3-benzothiopyranyl, respectively. Thiazolyl representspreferably 2- or 4-thiazolyl, and most preferred, 4-thiazolyl. Triazolylis preferably 1-, 2- or 5-(1,2,4-triazolyl). Tetrazolyl is preferably5-tetrazolyl. Heteroaryl moieties can be optionally substituted, asdefined below.

Preferably, heteroaryl is pyridyl, indolyl, quinolinyl, pyrrolyl,thiazolyl, isoxazolyl, triazolyl, tetrazolyl, pyrazolyl, imidazolyl,thienyl, furanyl, benzothiazolyl, benzofuranyl, isoquinolinyl,benzothienyl, oxazolyl, indazolyl, or any of the radicals substituted,especially mono- or di-substituted.

Substituents for the heteroaryl groups are varied and are selected from:-halogen, —OR′, —OC(O)R′, —NR′R″, —SR′, —R′, —CN, —NO₂, —CO₂R′,—CONR′R″, —C(O)R′, —OC(O)NR′R″, —NR″C(O)R′, —NR″C(O)₂R′,—NR′—C(O)NR″R′″, —NH—C(NH₂)═NH, —NR′C(NH₂)═NH, —NH—C(NH₂)═NR′, —S(O)R′,—S(O)₂R′, —S(O)₂NR′R″, —N₃, —CH(Ph)₂, perfluoro(C₁-C₄)alkoxy, andperfluoro(C₁-C₄)alkyl, in a number ranging from zero to the total numberof open valences on the aromatic ring system; and where R′, R″ and R′″are independently selected from hydrogen, (C₁-C₈)alkyl and C₃₋₈heteroalkyl, and phenyl.

As used herein, the terms “ring members” and “ring vertices” areintended to have the same meaning. For example, a six membered ring hassix ring vertices.

As used herein, the term “salt” refers to acid or base salts of thecompounds used in the methods of the present invention. Illustrativeexamples of pharmaceutically acceptable salts are mineral acid(hydrochloric acid, hydrobromic acid, sulfuric acid, phosphoric acid,and the like) salts, organic acid (acetic acid, propionic acid, glutamicacid, citric acid and the like) salts, quaternary ammonium (methyliodide, ethyl iodide, and the like) salts. It is understood that thepharmaceutically acceptable salts are non-toxic. Additional informationon suitable pharmaceutically acceptable salts can be found inRemington's Pharmaceutical Sciences, 17th ed., Mack Publishing Company,Easton, Pa., 1985, which is incorporated herein by reference.

Pharmaceutically acceptable salts of the acidic compounds of the presentinvention are salts formed with bases, namely cationic salts such asalkali and alkaline earth metal salts, such as sodium, lithium,potassium, calcium, magnesium, as well as ammonium salts, such asammonium, trimethyl-ammonium, diethylammonium, andtris-(hydroxymethyl)-methyl-ammonium salts.

Similarly, acid addition salts, such as of mineral acids, organiccarboxylic and organic sulfonic acids, e.g., hydrochloric acid,methanesulfonic acid, maleic acid, are also possible provided a basicgroup, such as pyridyl, constitutes part of the structure.

The neutral forms of the compounds can be regenerated by contacting thesalt with a base or acid and isolating the parent compound in theconventional manner. The parent form of the compound differs from thevarious salt forms in certain physical properties, such as solubility inpolar solvents, but otherwise the salts are equivalent to the parentform of the compound for the purposes of the present invention.

As used herein, the term “calcium salt” refers to salts containingcalcium. Examples of calcium salts include, but are not limited to,calcium acetate, calcium aluminates, calcium aluminosilicate, calciumarsenate, calcium borate, calcium bromide, calcium carbide, calciumcarbonate, calcium chlorate, calcium chloride, calcium citrate, calciumcitrate malate, calcium cyanamide, calcium dihydrogen phosphate, calciumfluoride, calcium formate, calcium glubionate, calcium glucoheptonate,calcium gluconate, calcium glycerylphosphate, calcium hexaboride,calcium hydride, calcium hydroxide, calcium hypochlorite, calciuminosinate, calcium iodate, calcium iodide, calcium lactate, calciumlactate gluconate, calcium magnesium acetate, calcium malate, calciumnitrate, calcium nitride, calcium oxalate, calcium oxide, calciumpangamate, calcium peroxide, calcium phosphate, calcium phosphide,calcium propionate, calcium pyrophosphate, calcium silicate, calciumsilicide, calcium sorbate, calcium stearate, calcium sulfate, calciumsulfide, calcium tartrate, calcium(I) chloride, dicalcium citrate,dicalcium phosphate, dodecacalcium hepta-aluminate, tricalciumaluminate, tricalcium phosphate and triple superphosphate. One of skillin the art will appreciate that other calcium salts are useful in thepresent invention.

As used herein, the term “hydrate” refers to a compound that iscomplexed to at least one water molecule. The compounds of the presentinvention can be complexed with from 1 to 10 water molecules. The term“hydrate” also includes hemi-hydrates, where there are two compounds forevery water molecules in the complex.

Certain compounds of the present invention possess asymmetric carbonatoms (optical centers) or double bonds; the racemates, diastereomers,geometric isomers and individual isomers are all intended to beencompassed within the scope of the present invention.

As used herein, the term “subject” refers to animals such as mammals,including, but not limited to, primates (e.g., humans), cows, sheep,goats, horses, dogs, cats, rabbits, rats, mice and the like. In certainembodiments, the subject is a human.

As used herein, the terms “therapeutically effective amount or dose” or“therapeutically sufficient amount or dose” or “effective or sufficientamount or dose” refer to a dose that produces therapeutic effects forwhich it is administered. The exact dose will depend on the purpose ofthe treatment, and will be ascertainable by one skilled in the art usingknown techniques (see, e.g., Lieberman, Pharmaceutical Dosage Forms(vols. 1-3, 1992); Lloyd, The Art, Science and Technology ofPharmaceutical Compounding (1999); Pickar, Dosage Calculations (1999);and Remington: The Science and Practice of Pharmacy, 20th Edition, 2003,Gennaro, Ed., Lippincott, Williams & Wilkins). In sensitized cells, thetherapeutically effective dose can often be lower than the conventionaltherapeutically effective dose for non-sensitized cells.

As used herein, the term “site of injury or localized condition” refersto a specific location in the subject's body that is in need oftreatment by the method of the present invention. For example, theinjury can be a fracture and the localized condition can be a diseasestate (such as osteoporosis, etc.) that is limited to a particularlocation in the subject's body, such as a particular bone, joint, digit,hand, foot, limb, spine, head, torso, etc. In some embodiments, the siteof injury or localized condition is a surgical implantation site.

As used herein, the term “promoting bone formation” refers tostimulating new bone formation, growing bone across a joint or gap,enhancing or hastening bone formation, and/or increasing bone density orbone mineral content. In some embodiments, a compound promotes boneformation if it increases the amount of bone in a sample by at least 3%,4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%,19%, 20%, or more relative to a control sample (e.g., a sample that hasnot been contacted with the compound).

As used herein, the term “arthrodesis” refers to the artificialinduction of joint ossification between two bones and/or across a joint,often via surgery. Arthrodesis can be accomplished via bone graft, metalimplants or the use of synthetic bone substitutes, among others.

As used herein, the term “bone autograft” refers to the grafting of asubject's own bone.

As used herein, the term “bone allograft” refers to the grafting of bonefrom one person to another person.

As used herein, the term “antiresorptive drug” refers to drugs that slowor block the resorption of bone and/or that act on the osteoclast cell.

As used herein, the term “bone related disease characterized by low bonemass” refers to bone having a T-score less than −0.5. Other methods ofdetermining low bone mass are known by one of skill in the art.

As used herein, the term “bone fracture” refers to bone that has beencracked, fractured, or broken in one or several locations along thebone. In some embodiments, the term “bone fracture” also includes asegment of the bond missing.

As used herein, the term “spinal fusion” refers to a surgical techniquefor combining or fusing two or more vertebrae.

As used herein, the term “structural support” refers to a segment of adevice that can be implanted in a subject (implantable portion). Thestructural support can be prepared from a variety of differentmaterials, including metals, ceramics, polymers and inorganic materials,such as described below. The structural support can be coated with avariety of materials that promote bone growth. In some embodiments, theentire device comprises an implantable structural support. For example,in some embodiments, an entire device as described herein can beimplanted at a surgical site and the surgical site can be closed overthe device.

As used herein, the term “external coating” refers to a coating of thestructural support that can cover only a portion of the structuralsupport (partial external coating) or cover the entire structuralsupport. For example, the partial external coating can completely coveronly the implantable portion of the structural support.

As used herein, the term “weakened bone,” “low bone density,” or “lowbone mass” refers to bone that has a T score of less than −0.5 (lessthan 0.9 g/cm2).

As used herein, the term “demineralized bone” refers to bone from whichthe inorganic mineral have been removed. The remaining organic collagenmaterial may contain the osteoinductive growth factors. These growthfactors include bone morphogenetic proteins that induce cartilage whichthen ossify via endochondral ossification to generate new boneformation. Demineralized bone often comes in the form of “demineralizedbone matrix (DBM).” DBM can be made by fresh frozen or freeze dried bulkbone allograft, or can be made from mild acid extraction of cadavericbone that removes the mineral phase, leaving collagen, growth factors,and noncollagenous proteins that offer the intrinsic properties ofosteoconduction. DBM can also be processed in a variety of ways,ultimately resulting in a powder that is mixed with a carrier to providethe optimum handling characteristics desired by a surgeon. DBM isclinically available in gels, pastes, putty, and fabrics that have beentailored to meet the needs of the surgical procedure. Some DBM are mixedwith antibiotics prior to the surgical procedure.

As used herein, the term “renal damage” refers to the inability of thekidneys to excrete waste and to help maintain the electrolyte balance ofthe body. Renal damage is characterized by some of the following: highblood pressure, accumulation of urea and formation of uremic frost,accumulation of potassium in the blood, decrease in erythropoietinsynthesis, increase in fluid volume, hyperphosphatemia, and metabolicacidosis, among others.

As used herein, the term “diabetes” refers to a condition primarilycharacterized by a body's inability to produce sufficient amounts ofinsulin, a hormone produced in the pancreas. When released in the bloodsteam, insulin induces cellular glucose uptake. As such, insufficientamounts of insulin result in elevated blood glucose levels in affectedindividuals. A person of skill in the art will recognize that the body'sinability to produce sufficient amounts of insulin can be acharacteristic of both Type 1 and Type 2 Diabetes.

As used herein, the term “osteoconductive matrix” refers to a materialthat can act as an osteoconductive substrate (i.e., permits bone growth)and has a scaffolding structure on which infiltrating cells can attach,proliferate, and participate in the process of producing osteoid, theorganic phase of bone, culminating in osteoneogenesis, or new boneformation. The terms “matrix” and “scaffold” interchangeably refer to astructural component or substrate intrinsically having a 3 dimensionalform upon which the specific cellular events involved in bone formationwill occur. The osteoconductive matrix allows for the ingrowth of hostcapillaries, perivascular tissue and osteoprogenitor cells. In someembodiments, an osteoconductive matrix includes an “osteoinductiveagent” for providing osteogenic potential. An osteoinductive agent, asused herein, is an agent that stimulates the host to multiply bonecells, thus producing more bone osteoid.

As used herein, the terms “treat,” “treating,” and “treatment” refers toany indicia of success in the treatment or amelioration of an injury,pathology, condition, or symptom (e.g., pain), including any objectiveor subjective parameter such as abatement; remission; diminishing ofsymptoms or making the symptom, injury, pathology or condition moretolerable to the patient; decreasing the frequency or duration of thesymptom or condition; or, in some situations, preventing the onset ofthe symptom or condition. The treatment or amelioration of symptoms canbe based on any objective or subjective parameter; including, e.g., theresult of a physical examination.

As used herein, the term “RankL inhibitor” refers to compounds or agentsthat inhibit the activity of RankL. RankL (Receptor Activator forNuclear Factor κ B Ligand), is important in bone metabolism byactivating osteoclasts. RankL inhibitors include, but are not limitedto, the human monoclonal antibody denosumab. One of skill in the artwill appreciate that other RankL inhibitors are useful in the presentinvention.

As used herein, the term “parathyroid hormone” or “PTH” refers tocompounds or agents that act on the PTH receptor to activate thepathway. PTH is important in bone metabolism by activating osteoblasts.PTH include, but are not limited to, Teriparatide, Forteo, andabaloparatide-SC. One of skill in the art will appreciate that other PTHare useful in the present invention.

As used herein, the term “combination therapy” is the use of the presentinvention in combination either together, or serially before or afterthe administration of compounds of this invention.

Certain compounds of the present invention possess asymmetric carbonatoms (optical centers) or double bonds; the racemates, diastereomers,geometric isomers, regioisomers and individual isomers (e.g., separateenantiomers) are all intended to be encompassed within the scope of thepresent invention. In some embodiments, the compounds of the presentinvention are a particular enantiomer or diastereomer substantially freeof other forms. The compounds of the present invention may also containunnatural proportions of atomic isotopes at one or more of the atomsthat constitute such compounds. For example, the compounds may beradiolabeled with radioactive or non-radioactive isotopes, such as forexample deuterium (²H), tritium (³H), iodine-125 (¹²⁵I) or carbon-14(¹⁴C). All isotopic variations of the compounds of the presentinvention, whether radioactive or not, are intended to be encompassedwithin the scope of the present invention.

III. COMPOUNDS AND COMPOSITIONS

In some embodiments, the present invention provides a compound accordingto Formula I:

or a salt, hydrate, prodrug, or isomer thereof, wherein

X is selected from CR^(3b) and N, wherein N is optionally oxidized tothe corresponding N-oxide;

Y is selected from CR^(3c) and N, wherein N is optionally oxidized tothe corresponding N-oxide;

Z is selected from CR^(3d) and N, wherein N is optionally oxidized tothe corresponding N-oxide,

provided that at least one of X, Y, and Z is N or the correspondingN-oxide;

A is

R^(N) is selected from the group consisting of heterocyclyl andheteroaryl, wherein

the heterocyclyl moiety is selected from monocyclic, fused bicyclic, andbridged cyclic, the monocyclic heterocyclyl comprising from 4 to 7 ringmembers, the fused bicyclic and bridged bicyclic heterocyclyl comprisingfrom 7 to 10 ring members, each heterocyclyl moiety having from 1 to 3heteroatoms as ring members selected from N, O, and S, wherein eachheterocyclyl moiety comprises at least one nitrogen atom as a ringmember and is optionally substituted with from 1 to 3R⁶ moieties,

the heteroaryl moiety comprises from 5 to 10 ring members, wherein atleast one ring member is a nitrogen atom and is optionally substitutedwith from 1 to 3R⁶ moieties,

each R², R^(3b), R^(3c) and R^(3d) is independently selected from thegroup consisting of H, halogen, C₁₋₆ alkyl, C₁₋₆ haloalkyl, C₂₋₆alkenyl, C₂₋₆ alkynyl, C₁₋₆ alkoxy, C₁₋₆ haloalkoxy, C₁₋₆ alkyl-OH,—O—C₁₋₆ alkyl-OH, C₃₋₆ cycloalkyl-C₁₋₄alkoxy, and —OH;

R⁶ is selected from the group consisting of —OH, C₁₋₃ alkyl, C₁₋₃alkyl-OH, —O—C₁₋₃ alkyl, C₃₋₄ heteroalkyl, C₁₋₃ haloalkyl, —O—C₁₋₃haloalkyl, halogen, and oxo.

In some embodiments, the present invention provides a compound accordingto Formula Ia:

wherein each variable position is as defined in Formula I.

In some embodiments, the present invention provides a compound accordingto Formula Ib:

wherein each variable position is as defined in Formula I.

In some embodiments, the present invention provides a compound accordingto Formula Ic:

wherein each variable position is as defined in Formula I.

In some embodiments, the present invention provides a compound accordingto Formula Id:

wherein each variable position is as defined in Formula I.

In some embodiments, each R² in Formulas I, Ia, Ib, Ic, or Id isindependently selected from the group consisting of halogen, C₁₋₆ alkyl,C₁₋₆ haloalkyl, and C₁₋₆ alkoxy. In some embodiments, R² in Formulas I,Ia, Ib, Ic, or Id is C₁₋₆alkyl or C₁₋₆ haloalkyl. In some embodiments,R² in Formulas I, Ia, Ib, Ic, or Id is CH₃ or CF₃. In some embodiments,R² in Formulas I, Ia, Ib, Ic, or Id is CF₃.

In some embodiments, each R^(3b), R^(3c) and R^(3d), when present inFormulas I, Ia, Ib, Ic, or Id is independently selected from the groupconsisting of H, halogen, C₁₋₆ alkyl, C₁₋₆ haloalkyl, C₁₋₆ alkoxy, C₁₋₆haloalkoxy. In some embodiments, each R^(3b), R^(3c) and R^(3d), whenpresent in Formulas I, Ia, Ib, Ic, or Id is H, halogen, and C₁₋₆ alkoxy.In some embodiments, each R^(3b), R^(3c) and R^(3d), when present inFormulas I, Ia, Ib, Ic, or Id is H, F, and methoxy. In some embodiments,at least one of R^(3b), R^(3c) and R^(3d) when present in Formulas I,Ia, Ib, Ic, or Id is F. In some embodiments, at least one of R^(3b),R^(3c) and R^(3d) when present in Formulas I, Ia, Ib, Ic, or Id ismethoxy. In some embodiments, at least one of R^(3b), R^(3c) and R^(3d)when present in Formulas I, Ia, Ib, Ic, or Id is F and at least one ofR^(3b), R^(3c) and R^(3d) is methoxy.

In some embodiments, R^(N) of Formulas I, Ia, Ib, Ic, or Id is aheteroaryl. In some embodiments, the heteroaryl moiety comprises from 4to 8 ring members, wherein at least one ring member is a nitrogen atomand is optionally substituted with from 1 to 3R⁶ moieties

In some embodiments, R^(N) of Formulas I, Ia, Ib, Ic, or Id is amonocyclic heterocyclyl.

In some embodiments, R^(N) in Formulas I, Ia, Ib, Ic, or Id is

In some embodiments, R⁶ in Formulas I, Ia, Ib, Ic, or Id is selectedform the group consisting of —OH, C₁₋₃ alkyl, C₁₋₃ alkyl-OH, —O—C₁₋₃alkyl, C₁₋₃ haloalkyl, haloalkyl, halogen, and oxo. In some embodiments,R⁶ in Formulas I, Ia, Ib, Ic, or Id is selected form the groupconsisting of C₁₋₃ alkyl, —O—C₁₋₃ alkyl, C₁₋₃ haloalkyl, —O—C₁₋₃haloalkyl, and halogen. In some embodiments, R⁵ is —OH, C₁₋₃ alkyl, or—O—-C₁₋₃alkyl.

In some embodiments, the present invention provides a compound FormulaI, wherein,

or a salt, hydrate, prodrug, or isomer thereof, wherein

R² is selected from the group consisting of H, C₁₋₆alkyl, and C₁₋₆haloalkyl,

R^(3c), if present, is H or C₁₋₆ alkoxy;

R^(3b) or R^(3d), if present, is H or halogen; and

A is

R^(N) is heterocyclyl or heteroaryl, and wherein

X, Y, and Z, and A are as defined in Formula I as well as thesubembodiments described herein.

In some embodiments, the present invention provides a compound FormulaI, wherein

or a salt, hydrate, prodrug, or isomer thereof, wherein

R² is H, C₁₋₆ haloalkyl, or C₁₋₆ alkyl;

R^(3c), if present, is C₁₋₆ alkoxy;

R^(3b) or R^(3d), if present, is H or halogen;

A is

and

R^(N) is

and

wherein X, Y, and Z as are defined above.

In some embodiments of the compound of Formula Ia, Ib, Ic, or Id

R² is C₁₋₆ alkyl or C₁₋₆ haloalkyl;

R^(3b), if present, is H or halogen;

R^(3c) is C₁₋₆ alkoxy; and

R^(N) is heterocyclyl or heteroaryl.

In some embodiments of the compound of Formula Ia, Ib, Ic, or Id

R² is C₁₋₆ haloalkyl;

R^(3b), if present, is H or halogen;

R^(3c) is C₁₋₆ alkoxy;

A is

and

R^(N) is

In some embodiments of the compound of Formula Ia, Ib, Ic, or Id

R² is CF₃; and

R^(3b), if present, is H or halogen;

R^(3c) is methoxy; and wherein

A is

and

R^(N) is as defined in Formula I as well as the subembodiments describedherein.

In one group of embodiments compounds of Formula I have a structureselected from the following:

In some embodiments, the invention provides a formate salt of a compoundaccording to any of the compounds described above. In some embodiments,the invention provides a citrate salt of a compound according to any ofthe compounds described above. In some embodiments, the inventionprovides a hydrochloride salt of a compound according to any of thecompounds described above.

The compounds and compositions of the present invention can also includehydrates, solvates, and prodrug forms. The compounds and compositions ofthe present invention can also include the isomers and metabolites ofcompounds of Formula I, Ia, Ib, Ic, or Id.

In some embodiments, the invention provides a pharmaceutical compositioncomprising a compound according to Formula I, Ia, Ib, Ic, or Id and apharmaceutically acceptable excipient.

The compounds of the present invention can be in the salt form. Saltsinclude, but are not limited, to sulfate, citrate, acetate, oxalate,chloride, bromide, iodide, nitrate, bisulfate, phosphate, acidphosphate, phosphonic acid, isonicotinate, lactate, salicylate, citrate,tartrate, oleate, tannate, pantothenate, bitartrate, ascorbate,succinate, maleate, gentisinate, fumarate, gluconate, glucaronate,saccharate, formate, benzoate, glutamate, methanesulfonate,ethanesulfonate, benzenesulfonate, p-toluenesulfonate, and pamoate(i.e., 1,1′-methylene-bis-(2-hydroxy-3-naphthoate)) salts. Other saltsinclude, but are not limited to, salts with inorganic bases includealkali metal salts such as sodium salts, and potassium salts; alkalineearth metal salts such as calcium salts, and magnesium salts; aluminumsalts; and ammonium salts. Other salts with organic bases include saltswith diethylamine, diethanolamine, meglumine, andN,N′-dibenzylethylenediamine. In some embodiments, the present inventionprovides the hydrochloride salt.

In some embodiments, the compounds of the present invention comprisenitrogen atoms which are optionally further oxidized, i.e., thecompounds are N-oxides. By way of example only, in one instance, anitrogen atom in a pyrido-indolyl ring system in a compound of FormulaI, Ia, Ib, Ic, or Id is oxidized to the corresponding N-oxide.

In some embodiments, the compounds described herein are delivered and/orformulated as prodrugs. In one embodiment, any compound described hereinis an ester prodrug. In another embodiment, any compound describedherein is an amide prodrug. In further embodiments, the prodrug moietiescomprise conjugated groups which allow selective targeting at a bonestructure. Examples of such motifs are described in Erez et al., Bioorg.Med. Chem. Lett. 2008, 18, 816-820 and Neale et al., Bioorg. Med. Chem.Lett. 2009, 19, 680-683 and are incorporated herein by reference.Accordingly, contemplated within the scope of embodiments presentedherein are estradiol conjugates and/or bisphosphonate conjugates ofcompounds of Formula I.

The compounds of the present invention can be made by a variety ofmethods known to one of skill in the art (see Comprehensive OrganicTransformations Richard C. Larock, 1989). One of skill in the art willappreciate that other methods of making the compounds are useful in thepresent invention. Exemplary methods for the synthesis of compounds ofFormula I, are described in the Examples section and in Scheme 1 below.

Starting with a compound 1, reaction with a compound 2 comprising aleaving group (LG) provides compounds of Formula I. Various leavinggroups are suitable including and not limited to halo, activated esters,mesylates, triflates or any other suitable leaving groups which allowfor the attachment of the group

at the 9-position of the core ring system. Optionally, where R^(3c) is amethoxy, it can be converted to a hydroxy group by demethylation usingprocedures described, for example, HBr in acetic acid, or borontribromide, or any other suitable procedure. Optionally, compounds ofFormula I comprise N-oxides which are prepared by oxidation using, forexample, chloroperbenzoic acid.

IV. METHODS OF PROMOTING BONE FORMATION

In another aspect, the present invention provides a method of promotingbone formation and fusion in a subject in need thereof, by administeringto the subject a therapeutically effective amount of a compound of thepresent invention (e.g., a compound or composition of Formula I, FormulaIa, Formula Ib, Formula Ic, or Formula Id as described in Section IIIabove).

In some embodiments, the present invention provides a method ofpromoting bone formation in a subject in need thereof, comprisingadministering to the subject a therapeutically effective amount of acompound of Formula I:

or a salt, hydrate, prodrug, or isomer thereof, wherein

X is selected from CR^(3b) and N, wherein N is optionally oxidized tothe corresponding N-oxide;

Y is selected from CR^(3c) and N, wherein N is optionally oxidized tothe corresponding N-oxide;

Z is selected from CR^(3d) and N, wherein N is optionally oxidized tothe corresponding N-oxide,

provided that at least one of X, Y, and Z is N or the correspondingN-oxide;

A is

R^(N) is selected from the group consisting of heterocyclyl andheteroaryl, wherein

the heterocyclyl moiety is selected from monocyclic, fused bicyclic, andbridged cyclic, the monocyclic heterocyclyl comprising from 4 to 7 ringmembers, the fused bicyclic and bridged bicyclic heterocyclyl comprisingfrom 7 to 10 ring members, each heterocyclyl moiety having from 1 to 3heteroatoms as ring members selected from N, O, and S, wherein eachheterocyclyl moiety comprises at least one nitrogen atom as a ringmember and is optionally substituted with from 1 to 3R⁶ moieties,

the heteroaryl moiety comprises from 5 to 10 ring members, wherein atleast one ring member is a nitrogen atom and is optionally substitutedwith from 1 to 3R⁶ moieties,

each R², R^(3b), R^(3c) and R^(3d) is independently selected from thegroup consisting of H, halogen, C₁₋₆ alkyl, C₁₋₆ haloalkyl, C₂₋₆alkenyl, C₂₋₆ alkynyl, C₁₋₆ alkoxy, C₁₋₆ haloalkoxy, C₁₋₆ alkyl-OH,—O—C₁₋₆ alkyl-OH, C₃₋₆ cycloalkyl-C₁₋₄alkoxy, and —OH;

R⁶ is selected from the group consisting of —OH, C₁₋₃ alkyl, C₁₋₃alkyl-OH, —O—C₁₋₃ alkyl, C₃₋₄ heteroalkyl, C₁₋₃ haloalkyl, —O—C₁₋₃haloalkyl, halogen, and oxo.

In some embodiments, the method comprises administering to the subject atherapeutically effective amount of hydrochloride salt, sulfate salt,formate salt or a citrate salt of a compound of Formula I, Formula Ia,Formula Ib, Formula Ic, or Formula Id.

One of skill in the art will appreciate that osteoblast mineral deposit(bone formation) can be achieved by local, systemic, or both local andsystemic administration. In some embodiments, bone formation is local. Asubject in need of local bone formation may have any of a variety ofailments or disease states (including but not limited to, weakened bone,fractured bone, or a disease or condition characterized by low bone massor poor mineralization as described herein). In some embodiments, thesubject is in need of a spinal fusion, bone fusion, arthrodesis, or anorthopedic, dental, or periodontal synthetic bone graft or implant. Insome embodiments, the present invention provides a method of promotingbone formation at a site of injury or localized condition. In someembodiments, the present invention comprises a method of fusing bones(e.g., at a site of injury). In some embodiments, the site of injury isa surgical site. In other embodiments, the injury is a fracture orweakened bone or periodontal disease.

In some embodiments, bone formation is systemic. Systemic bone formationrefers to the formation of bone throughout the subject, and can affectall the bones in the subject's body. A subject in need of systemic boneformation can suffer from any of a variety of ailments or diseasestates. In some embodiments, the subject suffers from a low bonemass/density condition/disease (either primary or secondary), a bonefracture, a periodontal disease/condition, or a disease/conditioncausing poor bone mineralization (e.g., ostoegenesis imperfect or HPP).Low bone mass can be determined by a variety of methods known to one ofskill in the art. For example, low bone mass/density can becharacterized by a T-score less than about −0.5. Low bone mass/densitydiseases/conditions include, but are not limited to, osteoporosis,osteopenia, and osteoporosispseudoglioma syndrome (OPPG), glucocorticoidinduced low bone mass/density, Osteogenesis imperfecta. In some otherembodiments, the low bone mass condition/disease can be osteopenia orosteoporosispseudoglioma syndrome (OPPG), HPP, or glycocorticoid inducedlow bone mass/density or other diseases which result in secondary lowbone density conditions.

Local and/or systemic bone formation using a compound or composition ofthe present invention can be achieved according to any of a variety ofmethods. Methods of formulating and administering the compounds andcompositions of the present invention (e.g., a compound or compositionof Formula I) are described in Section VII below. In some embodiments,the method of promoting bone formation comprises implanting a medicaldevice as described herein (e.g., in Section VIII below) to subject inneed thereof.

The methods of promoting osteoblast mineral deposits, ultimatelyincreasing bone mineralization or density, can be used to treat diseasescharacterized by secondary induced osteoporosis (low bone mass)including, but not limited to, osteomalacia, Polyostotic fibrousdysplasia, osteogenesis imperfecta, Paget's disease, rheumatoidarthritis, zero gravity, osteoarthritis, Prolonged inactivity orimmobility, arthrodesis, osteomyelitis, Celiac disease, Crohn's Disease,Ulcerative Colitis, inflammatory bowel disease, gastrectomy, secondaryinduced osteoporosis, Amennorhea, Cushing's Disease, Cushing's syndrome,Diabetes Mellitus, Diabetes, Eating Disorders, Hyperparathyroidism,Hyperthyroidism, Hyperphosphatasia (HPP), Hyperprolactinemia,Kleinefelter Syndrome, Thyroid Disease, Turner Syndrome, steroid inducedosteoporosis, seizure or depression induced osteoporosis, immobility,arthritis, cancer induced secondary osteoporosis, Gonadotropin releasinghormone agonists induced low bone mass, Thyroid medication induced lowbone mass, Dilantin (phenytoin), depakote induced low bone mass,chemotherapy induced low bone mass, Immunosuppressant induced low bonemass, Blood thinning agents induced low bone mass, Grave's disease,Juvenile rheumatoid arthritis, Malabsorption syndromes, Anorexianervosa, Kidney disease, Anticonvulsant treatment (e.g., for epilepsy),Corticosteroid treatment (e.g., for rheumatoid arthritis, asthma),Immunosuppressive treatment (e.g., for cancer), Inadequate nutrition(especially calcium, vitamin D), Excessive exercise leading toamenorrhea (absence of periods), Smoking, and Alcohol abuse,pregnancy-associated osteoporosis, copper deficiency, Dibasicaminoaciduria type 2, Werner's syndrome, Hajdu-Cheney syndrome,Hyperostosis corticalis deformans juvenilis, Methylmalonic aciduria type2, Cystathionine beta-synthase deficiency, Exemestane,Hyperimmunoglobulin E (IgE) syndrome, Haemochromatosis, Singleton-Mertensyndrome, Beta thalassaemia (homozygous), Reflex sympatheticosteodystrophy, Sarcoidosis, Winchester syndrome, Hallermann-Streiffsyndrome (HSS), Cyproterone, Glycerol kinase deficiency,Bonnet-Dechaume-Blanc syndrome, Prednisolone, Heparin, Gerodermaosteodysplastica, Torg osteolysis syndrome, Orchidectomy, Fabry'sdisease, Pseudoprogeria syndrome, Wolcott-Rallison syndrome, Ankylosingspondylitis, Myeloma, Systemic infantile hyalinosis, Albright'shereditary osteodystrophy, Anorexia Nervosa, AutoimmuneLymphoproliferative Syndrome, Brown-Sequard Syndrome, Diamond-Blackfananemia, Eating disorders, Galactorrhoea-Hyperprolactinaemia, Gonadaldysgenesis, Kidney conditions, Menkes Disease, Menopause, Neuritis,Ovarian insufficiency due to FSH resistance, Familial Ovarianinsufficiency, Premature aging, Primary biliary cirrhosis, Prolactinoma,Familial Prolactinoma, Renal osteodystrophy, Ulcerative colitis,Underweight, Werner syndrome, Bone tumor, Bone cancer, Brittle bonedisease, Osteonecrosis, Osteogenesis imperfecta congenita, Osteogenesisimperfecta tarda, osteogenesis imperfecta, glucocorticoid inducedosteopenia/osteoporosis and periodontal disease. One of skill in the artwill appreciate that other types of conditions, diseases and treatmentsalso lead to osteoporosis.

Bone formation can be measured according to any of a variety of waysknown to one of skill in the art. Methods of measuring bone formationinclude, but are not limited to, uCT (micro CT), Dual X-ray absorption(Bone density), ultrasound, QCT, SPA, DPA, DXR, SEXA, QUS, X-ray, usingthe human eye during surgically manipulation, Alizarin red S, serumosteocalcin, serum alkaline phosphatase, Serum bone Gla-protein (BGP),bone mineral content, bone ash weight, serum calcium, serum phosphorus,tantalum markers, and serum IGF-1.

Many indicators of bone formation can be used to measure and/or quantifythe amount of bone formation, including bone density. In someembodiments, bone formation can be demonstrated by an increase of 0.1%in bone density. In other embodiments, bone growth can be demonstratedby an increase of 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%,2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 12%, 14%, 16%, 18%, 20%, 30%, 40%,50%, 60%, 70%, 80%, 90%, 100%, 200%, 300%, 400%, 500%, 600%, 700%, 800%,900% or 1000% or greater, in bone density. Bone density can be measuredby a variety of different methods, including the T-score and Z-score.The Z-score is the number of standard deviations above or below the meanfor the patient's age and sex. The T-score is the number of standarddeviations above or below the mean for a healthy 30 year old adult ofthe same sex as the patient. Low bone mass is characterized by a T-scoreof −1 to −2.5. Osteoporosis is characterized by a T-score less than−2.5. Improvement in the T-score or Z-score indicate bone growth. Bonedensity can be measured in a variety of places of the skeleton, such thespine or the hip. One of skill in the art will appreciate that othermethods of determining bone density are useful in the present invention.

V. METHODS OF TREATING RENAL DAMAGE

In another aspect, the present invention provides a method of treatingrenal damage by administering to a subject suffering from renal damage,a therapeutically effective amount of a compound of the presentinvention (e.g., a compound or composition of Formula I, as described inSection III above).

Renal damage can be caused by a variety of ailments known to one ofskill in the art. In some embodiments, renal damage is caused byinfection, radiation, toxin, dehydration or trauma. Toxins causing renaldamage include, but are not limited to, chemicals, poisons, andchemotherapeutic agents. One of skill in the art will appreciate thatother causes of renal damage can be treated by the methods of thepresent invention.

Renal damage treatable by the compounds of the present inventionincludes acute renal failure. Acute renal failure is also known as acutekidney failure or acute kidney injury. Acute renal failure results inretention of nitrogenous (urea and creatinine) and non-nitrogenous wasteproducts that are normally excreted by the kidney. Depending on theseverity and duration of the renal dysfunction, this accumulation isaccompanied by metabolic disturbances, such as metabolic acidosis(acidification of the blood) and hyperkalaemia (elevated potassiumlevels), changes in body fluid balance, and effects on other organsystems. Acute renal failure can be characterized by oliguria or anuria(decrease or cessation of urine production), although nonliguric acuterenal failure can also occur.

A subject can be characterized as being at (1) a risk for acute damage;(2) kidney damage resulting in injury; (3) acute renal failure; and (4)loss of kidney function. Risk for acute kidney damage is characterizedby serum creatinine increased 1.5 times or urine production of <0.5ml/kg body weight over 6 hours. Injury is reached when serum creatinineincreased 2.0 times or urine production<0.5 ml/kg over 12 hours. Failureis reached when serum creatinine increased 3.0 times or creatinine>355μM (with a rise of >44) or urine output below 0.3 ml/kg over 24 hours.Loss of kidney function is reached when a subject suffers frompersistent acute renal failure or more than four weeks of complete lossof kidney function.

Kidney biopsy can be performed in the setting of acute renal failure, toprovide a definitive diagnosis and sometimes an idea of the prognosis,unless the cause is clear and appropriate screening investigations arereassuringly negative.

Renal therapeutic agents of the invention can be used in subjects thathave received renal injury, or those at risk of chronic renal failure.As used herein, a subject is said to be in, or at risk for, chronicrenal failure, or at risk of the need for renal replacement therapy(i.e., chronic hemodialysis, continuous peritoneal dialysis, or kidneytransplantation), if the subject is reasonably expected to suffer aprogressive loss of renal function associated with progressive loss offunctioning nephron units. Whether a particular subject is in, or atrisk of, chronic renal failure is a determination which may routinely bemade by one of ordinary skill in the relevant medical or veterinary art.Subjects in, or at risk of, chronic renal failure, or at risk of theneed for renal replacement therapy, include but are not limited to thefollowing: subjects which can be regarded as afflicted with chronicrenal failure, end-stage renal disease, chronic diabetic nephropathy,hypertensive nephrosclerosis, chronic glomerulonephritis, hereditarynephritis, and/or renal dysplasia; subjects having a biopsy indicatingglomerular hypertrophy, tubular hypertrophy, chronic glomerulosclerosis,renal cell carcinoma, and/or chronic tubulointerstitial sclerosis;subjects having an ultrasound, MRI, CAT scan, or other non-invasiveexamination indicating renal fibrosis; subjects having an unusual numberof broad casts present in urinary sediment; subjects having a GFR whichis chronically less than about 50%, and more particularly less thanabout 40%, 30% or 20%, of the expected GFR for the subject; human malesubjects weighing at least about 50 kg and having a GFR which ischronically less than about 50 ml/min, and more particularly less thanabout 40 ml/min 30 ml/min or 20 ml/min; human female subjects weighingat least about 40 kg and having a GFR which is chronically less thanabout 40 ml/min, and more particularly less than about 30 ml/min, 20ml/min or 10 ml/min; subjects possessing a number of functional nephronunits which is less than about 50%, and more particularly less thanabout 40%, 30% or 20%, of the number of functional nephron unitspossessed by a healthy but otherwise similar subject; subjects whichhave a single kidney; and subjects which are kidney transplantrecipients.

VI. METHODS OF TREATING DIABETES

The compounds and compositions of the present invention are also usefulin the treatment of diabetes. Accordingly, some embodiments of theinvention provide a method of treating diabetes. The method includesadministering to a subject in need thereof a therapeutically effectiveamount of a compound of the present invention (e.g., a compound orcomposition of Formula I, Formula Ia, Formula Ib, Formula Ic, or FormulaId as described in Section III above).

Diabetes is a disease where the body is unable to produce any or enoughinsulin causing elevated blood glucose levels in afflicted individuals.Without being bound to any particular theory, it is believed that thecompounds and compositions of the present invention help to treatdiabetes by regenerating pancreatic cells. In some embodiments, thecompounds of the present invention are believed to induce regenerationof beta cells in the pancreas. See, for example, Wang P. et al., NatMed., 21(4):383-388 (2015).

Diabetic therapeutic agents of the invention can be used in subjectsthat have received a pancreatic injury, are in a pre-diabetic state orare diabetic. As used herein a subject that is said to have receivedpancreatic injury is one that has reduced, compromised, or no nativeproduction of insulin. Whether a subject is considered pre-diabetic ordiabetic depends on a number of factors including the subjects fastingblood glucose level. A subject is considered pre-diabetic with a fastingblood glucose level is above 100 mg/dL. A subject is considered diabeticif the subjects fasting blood glucose level is above 125 mg/dL.

Pancreatic injury can be caused by a variety of ailments known to one ofskill in the art. In some embodiments, pancreatic damage is caused byinfection, autoimmune disease, radiation, toxin, or trauma. Toxinscausing pancreatic include, but are not limited to, chemicals, poisons,and chemotherapeutic agents. One of skill in the art will appreciatethat other causes of pancreatic damage can be treated by the methods ofthe present invention.

In some embodiments, the disease being treated is Type 1 Diabetes. Insome embodiments, the disease being treated is Type 2 Diabetes.

The compounds of the present invention may be administered in series orin combination with other therapeutic agents useful in treatingdiabetes. In some embodiments, the other therapeutic agents areantidiabetic agents. Diabetic agents include, but are not limited to,lipid-lowering/lipid-modulating agents, agents for treating diabeticcomplications, anti-obesity agents, antihypertensive agents, SGLT1inhibitors, SGLT2 inhibitors, antihyperuricemic agents, and agents fortreating chronic heart failure, atherosclerosis or related disorders.

VII. METHODS OF TREATING BONE LOSS

In another aspect, the present invention provides a method of treatingbone loss by administering to a subject suffering from bone loss, atherapeutically effective amount of a compound of the present invention(e.g., a compound or composition of Formula I, Formula Ia, Formula Ib,Formula Ic, or Formula Id as described in Section III above).

As diagramed in FIG. 1, bone density in an individual can be describedby the net loss (bone resorption) and gain (bone formation) of bonemass. In individuals with bone loss, the net bone resorption is greaterthan the bone formation causing a decrease in bone loss. It iscontemplated that in particular embodiments of this invention, bone lossmay be treated by inhibiting or reducing bone resorption whilestimulating or encouraging bone formation.

Antiresorptive agents are compounds which slow the process of boneresorption. Antiresorptive agents include, but are not limited to, RankLinhibitors, Denosumab, Prolia, Cathepsin-K modulators, Alendronate,Fosamax, selective estrogen receptor modulators (SERMS), Calcium,Estrogen, Bisphosphonates, and Calcitonin.

The compounds and compositions of the present invention treat bone lossby promoting bone formation. When the compounds of the present inventionare administered sequentially or combination with one or moreantiresorptive agents, both the rate of bone resorption is inhibited orreduced and the rate of bone formation is stimulated.

The compounds and compositions of the present invention and theantiresorptive agents described herein may be administered sequentiallyor in combination. Further details of combination therapy are discussedin section IX. C., below.

The compounds and compositions of the present invention treat bone lossby promoting bone formation. In some embodiments, when the compounds ofthe present invention are administered sequentially with one or moreantiresorptive agents, the rate of bone resorption is inhibited orreduced and the amount of bone formation is maintained.

The compounds and compositions of the present invention may beadministered to patients who have been treated with an antiresorptive,thus serilally, or patients may be administered sequentially with one ormore antiresorptive agents, whereby the rate of bone resorption isinhibited or reduced and the amount of bone formation is maintained.

VIII. METHODS OF TREATING CANCER

The compounds and compositions of the present invention are also usefulin the treatment of cancer. Accordingly, some embodiments of theinvention provide a method of treating cancer. The method includesadministering to a subject in need thereof a therapeutically effectiveamount of a a compound of the present invention (e.g., a compound orcomposition of Formula I, Formula Ia, Formula Ib, Formula Ic, or FormulaId as described in Section III above).

In some embodiments, the compounds of the present invention are usefulin the treatment of proliferative disorders such as cancers, leukaemiasand other disorders associated with uncontrolled cellular proliferationsuch as psoriasis and restenosis. As defined herein, ananti-proliferative effect within the scope of the present invention maybe demonstrated by the ability to inhibit cell proliferation in an invitro whole cell assay, for example using any of the cell lines A549,HT29, Saos-2, HeLa or MCF-7, or by showing inhibition of a CDK enzyme(such as CDK2 or CDK4), MTT or BRDU in an appropriate assay. Using suchcell line and enzymes assays it may be determined whether a compound isanti-proliferative in the context of the present invention.

As used herein, the term “cancer” includes, but is not limited to thefollowing cancers: breast, ovary, cervix, prostate, testis,genitourinary tract, esophagus, larynx, glioblastoma, neuroblastoma,stomach, skin, keratoacanthoma, lung, epidermoid carcinoma, large cellcarcinoma, small cell carcinoma, lung adenocarcinoma, bone, colon,adenoma, pancreas, adenocarcinoma, thyroid, follicular carcinoma,undifferentiated carcinoma, papillary carcinoma, seminoma, melanoma,sarcoma, bladder carcinoma, liver carcinoma and biliary passages, kidneycarcinoma, myeloid disorders, lymphoid disorders, Hodgkin's, hairycells, buccal cavity and pharynx (oral), lip, tongue, mouth, pharynx,small intestine, colon-rectum, large intestine, rectum, brain andcentral nervous system, and leukemia. One of skill in the art willappreciate that other cancers and proliferative disorders can be treatedby the compounds and compositions of the present invention.

In some embodiments, the cancer is bone cancer, colon cancer, multiplemyeloma, gastric cancer, colorectal cancer, prostate cancer, cervicalcancer, lung cancer, pancreatic cancer, medulloblastoma, liver cancer,parathyroid cancer, endometrial cancer, or breast cancer. In someembodiments, the cancer is bone cancer. In some embodiments, the canceris a cancer that is characterized by secondary low bone mass, includingbut not limited to, breast cancer and prostate cancer. In someembodiments, the cancer is a cancer that has metastasized to bone.

IX. FORMULATION AND ADMINISTRATION

In some embodiments, the present invention provides a pharmaceuticalcomposition including a compound as described herein (e.g., a compoundor composition of Formula I, as described in Section III above) and apharmaceutically acceptable excipient. In other embodiments, thecomposition further comprises an osteoconductive matrix.

The compositions of the present invention can be in the form of apharmaceutical composition containing the antagonist and apharmaceutically acceptable carrier. Pharmaceutically acceptablecarriers are well known in the art and include aqueous solutions such asphysiologically buffered saline or other buffers or solvents or vehiclessuch as glycols, glycerol, oils such as olive oil or injectable organicesters. The selection of a pharmaceutically acceptable carrier willdepend, in part, on the chemical nature of the compound.

The compounds of the present invention can be formulated in a variety ofdifferent manners known to one of skill in the art. Pharmaceuticallyacceptable carriers are determined in part by the particular compositionbeing administered, as well as by the particular method used toadminister the composition. Accordingly, there are a wide variety ofsuitable formulations of pharmaceutical compositions of the presentinvention (see, e.g., Remington's Pharmaceutical Sciences, 20^(th) ed.,2003, supra).

A pharmaceutically acceptable carrier may include physiologicallyacceptable compounds that act, for example, to stabilize the compositionor increase its absorption, or other excipients as desired.Physiologically acceptable compounds include, for example,carbohydrates, such as glucose, sucrose, dextrans, dextrins,cyclodextrins, or captisol, antioxidants, such as ascorbic acid orglutathione, chelating agents, low molecular weight proteins or otherstabilizers or excipients. One skilled in the art would know that thechoice of a pharmaceutically acceptable carrier, including aphysiologically acceptable compound, depends, for example, on the routeof administration and on its particular physio-chemical characteristics.

Generally, such carriers should be nontoxic to recipients at the dosagesand concentrations employed. Ordinarily, the preparation of suchcompositions entails combining the therapeutic agent with buffers,antioxidants such as ascorbic acid, low molecular weight (less thanabout 10 residues) polypeptides, proteins, amino acids, carbohydratesincluding glucose, maltose, sucrose dextrans, dextrins, cyclodextrins,or captisol, chelating agents such as EDTA, glutathione and otherstabilizers and excipients. Neutral buffered saline or saline mixed withnonspecific serum albumin are exemplary appropriate diluents.

The amount of a compound or composition of the present invention (e.g.,a compound or composition of Formula I, as described herein) that isadministered to an individual will depend, in part, on the diseaseand/or extent of injury. Methods for determining an effective amount ofan agent to administer for a diagnostic or a therapeutic procedure arewell known in the art and include phase I, phase II and phase IIIclinical trials, or the Pilot and Pivotal trials (FDA device approvalpathway). Generally, an agent is administered in a dose of about 0.0001to 500 mg/kg body weight when administered systemically, and at aconcentration of approximately 0.1 nM to 1000 μM when administereddirectly to a wound site.

The total amount of the compound or composition can be administered to asubject as a single dose, either as a bolus or by infusion over arelatively short period of time, or can be administered using afractionated treatment protocol, in which the multiple doses areadministered over a more prolonged period of time. One skilled in theart would know that the concentration of a particular compound orcomposition that is needed to provide an effective amount to a region orregions of injury depends on many factors, including the age and generalhealth of the subject as well as the route of administration, the numberof treatments to be administered, and the nature of the compound. Inview of these factors, the skilled artisan would adjust the particulardose so as to obtain an effective amount for efficaciously promotingbone formation for therapeutic purposes.

The pharmaceutical preparation is preferably in unit dosage form. Insuch form the preparation is subdivided into unit doses containingappropriate quantities of the active component. The unit dosage form canbe a packaged preparation, the package containing discrete quantities ofpreparation, such as packeted tablets, capsules, transdermal patches,ampoules, and powders in vials, ampoules, or on an osteoconductivematrix. Also, the unit dosage form can be a capsule, tablet, cachet, orlozenge itself, or it can be the appropriate number of any of these inpackaged form. The composition can, if desired, also contain othercompatible therapeutic agents. Preferred pharmaceutical preparations candeliver the compounds of the invention in a sustained releaseformulation.

In some embodiments, the methods of the present invention includeapplication of the compounds as described herein in cocktails includingother medicaments, for example, antibiotics, fungicides, anabolic boneagents, antiresoptive agents, and/or anti-inflammatory agents.Alternatively, the methods may comprise sequential dosing of anafflicted individual with a compound as described herein and one or moreadditional medicaments to optimize a treatment regime. In such optimizedregimes, the medicaments, including the compounds of this invention, canbe applied in any sequence and in any combination.

Individuals to be treated with the compounds and compositions of thepresent invention can be any mammal, for example, a human or a non-humanmammal, e.g., a primate, dog, cat, horse, cow, goat, sheep, pig, mouse,or rat, or any commercially important animal or domesticated animal.

In some embodiments, an individual to be treated according to themethods of the present invention is an individual who has received or isreceiving an antiresorptive therapeutic agent. For example, in someembodiments, antiresorptive therapy may be administered concurrentlywith a compound or composition of the present invention. In someembodiments, antiresorptive therapy and therapy with a compound orcomposition of the present invention are administered sequentially(either antiresorptive therapy preceding therapy with a compound orcomposition of the present invention, or therapy with a compound orcomposition of the present invention preceding antiresorptive therapy).In some embodiments, the individual may have been previously treatedwith an antiresorptive agent. In some embodiments, an individual may beconcurrently treated with an antiresorptive agent during a first portionof the treatment course for the compound or composition of the presentinvention but may discontinue treatment with the antiresorptive agentduring a second portion of the treatment course. In some embodiments, anindividual to be treated according to the methods of the presentinvention has not been treated with an antiresorptive agent. In someembodiments, an individual is treated with an antiresorptive agent afterbeing treated with a compound or composition of the present invention.

In some embodiments, an individual to be treated according to themethods of the present invention is an individual who has received or isreceiving a combination of antiresorptive and/or bone anabolictherapeutic agents. For example, in some embodiments, antiresorptiveand/or bone anabolic therapy may be administered concurrently with acompound or composition of the present invention. In some embodiments,antiresorptive and/or bone anabolic therapy and therapy with a compoundor composition of the present invention are administered sequentially(either antiresorptive therapy preceding therapy with a compound orcomposition of the present invention, or therapy with a compound orcomposition of the present invention preceding antiresorptive therapy).In some embodiments, the individual may have been previously treatedwith an antiresorptive and/or bone anabolic agent. In some embodiments,an individual may be concurrently treated with an antiresorptive and/orbone anabolic agent during a first portion of the treatment course forthe compound or composition of the present invention but may discontinuetreatment with the antiresorptive and/or bone anabolic agent during asecond portion of the treatment course. In some embodiments, anindividual to be treated according to the methods of the presentinvention has not been treated with an antiresorptive agent and/or boneanabolic. In some embodiments, an individual is treated with anantiresorptive and/or bone anabolic agent after being treated with acompound or composition of the present invention.

In some embodiments, the compounds and compositions of the presentinvention are administered systemically. In some embodiments, thecompounds and compositions of the present invention are administeredlocally.

A. Systemic Delivery

In some embodiments, the compounds and compositions of the presentinvention are administered systemically. Systemic administration of thecompounds and compositions of the present invention can be used, forexample, for the treatment of a systemic disease or conditioncharacterized by whole body effects, i.e., low bone mass (e.g.,osteoporosis), diabetes, cancer, or kidney disease.

The pharmaceutical compositions of the present invention can be preparedfor administration by a variety of different routes. In general, thetype of carrier is selected based on the mode of administration.Pharmaceutical compositions can be formulated for any appropriate mannerof administration, including, for example, topical, oral, nasal,intrathecal, rectal, vaginal, sublingual or parenteral administration,including subcutaneous, intravenous, intramuscular, intrasternal,transdermal, intracavernous, intrameatal, or intraurethral injection orinfusion. A pharmaceutical composition (e.g., for oral administration ordelivery by injection) can be in the form of a liquid (e.g., an elixir,syrup, solution, emulsion or suspension). A liquid pharmaceuticalcomposition may include, for example, one or more of the following:sterile diluents such as water for injection, saline solution,preferably physiological saline, Ringer's solution, isotonic sodiumchloride, fixed oils that may serve as the solvent or suspending medium,polyethylene glycols, glycerin, propylene glycol or other solvents;antibacterial agents; antioxidants; chelating agents; buffers such asacetates, citrates or phosphates and agents for the adjustment oftonicity such as sodium chloride or dextrose. A parenteral preparationcan be enclosed in ampoules, disposable syringes or multiple dose vialsmade of glass or plastic. The use of physiological saline is preferred,and an injectable pharmaceutical composition is preferably sterile.

The formulations of the invention are also suitable for administrationin all body spaces/cavities, including but not limited to pleura,peritoneum, cranium, mediastinum, pericardium, bursae or bursal,epidural, intrathecal, intraocular, intra-articular, intra-discal,intra-medullary, perispinal, etc.

Formulations suitable for oral administration can consist of (a) liquidsolutions, such as an effective amount of a compound of the presentinvention suspended in diluents, such as water, saline or PEG 400; (b)capsules, sachets, depots or tablets, each containing a predeterminedamount of the active ingredient, as liquids, solids, granules orgelatin; (c) suspensions in an appropriate liquid; (d) suitableemulsions; and (e) patches. The pharmaceutical forms can include one ormore of lactose, sucrose, mannitol, sorbitol, calcium phosphates, cornstarch, potato starch, dextrans, dextrins, cyclodextrins, captisol,microcrystalline cellulose, gelatin, colloidal silicon dioxide, talc,magnesium stearate, stearic acid, and other excipients, colorants,fillers, binders, diluents, buffering agents, moistening agents,preservatives, flavoring agents, dyes, disintegrating agents,pharmaceutically compatible carriers, and other ingredients categorizedby the FDA as inert ingredients. Lozenge forms can comprise the activeingredient in a flavor, e.g., sucrose, as well as pastilles comprisingthe active ingredient in an inert base, such as gelatin and glycerin orsucrose and acacia emulsions, gels, and the like containing, in additionto the active ingredient, carriers known in the art.

Particular oral formulations suitable for the present invention include,but are not limited to, buffered aqueous solutions from pH 4 to 10;unbuffered aqueous systems from pH 2 to 10; cosolvent aqueous solutionscomprising propylene glycol, glycerol, ethanol, or combinations thereof;aqueous solutions comprising one or more emulsifying agents such as oneor more saturated polyglycolysed glycerides (e.g. Gelucire®); aqueoussuspensions comprising methylcellulose (optionally including sodiumdodecyl sulfate, sodium laurel sulfate, docusate, or polysorbate 80 atsub-critical micelle concentrations (CMC)); aqueous solutions comprisinga cyclodextrin (e.g. hydroxypropyl-β-cyclodextrin or sulfobutylether-β-cyclodextrin); solutions comprising one or more vegetable oils(e.g. safflower oil, soybean oil, oleic acid, etc.); non-aqueoussolutions with or without emulsifying agents such as PEG400 or 600,soybean oil/polysorbate 80/sorbitan fatty acid ester (Span 80),mono/diglyceride or capric/caprilic acid (IMWITOR 742)/polysorbate 80(70:30), polyethoxylated palm kernel oil/polyethylene glycol (PEG) 400or 600/water; an aqueous surfactant solution comprising polysorbate 80and SDS or SLS; oil suspensions comprising soybean oil and saffloweroil; and preparing a compound or composition of the present invention innanoparticles.

Formulations suitable for intravenous bolus injection of the compound orcomposition include, but are not limited to, aqueous solutionscomprising buffered or unbuffered saline, optionally including dextrose;cosolvent systems comprising glycerin, ethanol, propylene glycol, PEG300 or 400, glycofural, N-methylpyrrolidone (NMP), dimethylacetamide(DMA), dimethylformamide (DMF), dimethylisosorbide (DMI), dimethylsulphoxide (DMSO), or a combination thereof in water; aqueous surfactantsolutions comprising polysorbate 80; aqueous solutions comprising acyclodextrin (e.g. hydroxypropyl-β-cyclodextrin or sulfobutylether-β-cyclodextrin); oily emulsions; plasma; and aqueous suspensionsoptionally comprising methylcellulose and/or sodium dodecyl sulfate,sodium laurel sulfate, docusate, or polysorbate 80 at sub-criticalmicelle concentrations (CMC))

Formulations suitable for intravenous infusion of the compound orcomposition include, but are not limited to, aqueous solutionscomprising buffered or unbuffered saline, optionally including dextrose,mannitol, or lactose; or any of the above listed formulations forintravenous bolus injection.

Formulations suitable for intramuscular, subcutaneous, orintraperitoneal administration include, but are not limited to,solutions in oil comprising soybean oil, peanut oil, sesame oil, ethyloleate, isopropyl myristate, polysorbate 80, or sorbitan fatty acidester; aqueous suspensions comprising water, buffered or unbufferedsaline, or dextrose (in water); or any of the above listed formulationsfor intravenous bolus injection.

Formulations suitable for ocular administration include, but are notlimited to, buffered or unbuffered aqueous solutions from pH 4 to 9 suchas saline, optionally the aqueous solution may include hydroxyethylcellulose; aqueous suspensions; or oily emulsions comprising, forexample, mineral oil, peanut oil, or petrolatum.

Typical formulations for topical/transdermal administration includecreams, ointments, sprays, lotions, and patches. Topical/transdermalformulations of the present disclosure comprise propylene glycol,isopropyl mystate, PEG 300, PEG 400, petroaltum or mixtures thereof,optionally ethanol or isopropanol may also be included.

The compounds of the present invention may also be included in slowrelease formulations for prolonged treatment following a single dose. Inone embodiment, the formulation is prepared in the form of microspheres.The nanoparticle/microspheres can be prepared as a homogenous matrix ofa compound with a biodegradable controlled release material, withoptional additional medicaments as the treatment requires. Thenanoparticle/microspheres are preferably prepared in sizes suitable forinfiltration and/or injection, and injected systemically, or directly atthe site of treatment.

Some slow release embodiments include polymeric substances that arebiodegradable and/or dissolve slowly. Such polymeric substances includepolyvinylpyrrolidone, low- and medium-molecular-weight hydroxypropylcellulose and hydroxypropyl methylcellulose, cross-linked sodiumcarboxymethylcellulose, carboxymethyl starch, potassiummethacrylatedivinylbenzene copolymer, polyvinyl alcohols, starches,starch derivatives, microcrystalline cellulose, ethylcellulose,methylcellulose, and cellulose derivatives, β-cyclodextrin, captisol,poly(methyl vinyl ethers/maleic anhydride), glucans, scierozlucans,mannans, xanthans, alzinic acid and derivatives thereof, dextrinderivatives, glyceryl monostearate, semisynthetic glycerides, glycerylpalmitostearate, glyceryl behenate, polyvinylpyrrolidone, gelatine,agnesium stearate, stearic acid, sodium stearate, talc, sodium benzoate,boric acid, and colloidal silica.

Slow release agents of the invention may also include adjuvants such asstarch, pregelled starch, calcium phosphate mannitol, lactose,saccharose, glucose, sorbitol, microcrystalline cellulose, gelatin,polyvinylpyrrolidone. methylcellulose, starch solution, ethylcellulose,arabic gum, tragacanth gum, magnesium stearate, stearic acid, colloidalsilica, glyceryl monostearate, hydrogenated castor oil, waxes, andmono-, bi-, and trisubstituted glycerides. Slow release agents may alsobe prepared as generally described in WO94/06416.

B. Local Delivery

In some embodiments, the compounds and compositions of the presentinvention are administered locally. Local administration of thecompounds and compositions of the present invention can be used, forexample, for fracture healing, fusion (e.g., arthrodesis), orthopedicreconstruction, and periodontal repair. In some embodiments, localadministration comprises administering a compound or composition inconjunction with a suitable carrier material capable of maintaining thecompound at an in vivo site of application or capable of providingstructural load. In some embodiments, the carrier is biocompatible, amatrix, in vivo biodegradable or resorbable, and/or porous enough toallow cell infiltration. In some embodiments, a compound or compositionof the present invention (e.g., a compound or composition of Formula I)is administered locally via an implantable medical device.

The compounds and compositions of the present invention are useful inclinical applications in conjunction with a suitable delivery or supportsystem (e.g., a scaffold or matrix as described herein). As disclosedherein, the matrix can be combined with a compound or composition ofFormula I to induce bone formation reliably and reproducibly in amammalian body. The matrix preferably includes particles of porousmaterials. The pores are preferred to be of a dimension to permitprogenitor cell migration into the matrix and subsequent differentiationand proliferation. In some embodiments, the pore size of the matrix isat least 5 μm, e.g., at least 5, 10, 15, 20, 25, 30, 40, 50, 60, 70, 80,90, 100, 125, 150, 175, 200, 250, 300, 400, 450, 500, 550, 600, 650,700, 750, 800, 850, 900, 950, 1000, 1200, 1500, 1700, or 2000 μm. Thematrix can be fabricated by close packing particulate material into ashape spanning the bone defect, or by otherwise structuring as desired amaterial that is biocompatible, and preferably biodegradable orresorbable in vivo to serve as a “temporary scaffold” and substratum forrecruitment of migratory progenitor cells, and as a base for theirsubsequent anchoring and proliferation. In some embodiments, thescaffold or matrix comprises a mesh structure, a foam structure, asponge structure, or a fiber structure.

A scaffold or matrix for use in delivering a compound of the presentinvention can comprise a synthetic, a biologic material, or acombination thereof In some embodiments, the scaffold or matrixcomprises a naturally occurring polymer, a synthetic biodegradablepolymer, a synthetic nonbiodegradable polymer, a bioceramic, a bioglass,or combinations thereof. Natural and synthetic polymers, bioceramics,and bioglasses for use in scaffolds are known in the art. See, e.g.,Dhandayuthapani et al., International Journal of Polymer Science, volume2011, article ID 290602 (2011), incorporated by reference herein.Natural polymers include, but are not limited to, proteins (e.g., silk,collagen, gelatin, fibrinogen, elastin, keratin, actin, and myosin),polysaccharides (e.g., cellulose, amylose, dextran, chitin, chitosan,and glycosaminoglycans), and polynucleotides (e.g., DNA and RNA).Synthetic polymers include, but are not limited to, PLA, PGA, PLLA,PLGA, PCL, PLDLA, PDS, PGCL, PEA, PCA, PDLLA, PEU, and PBT. Bioceramicsand bioglasses include, but are not limited to, HAP, TCP, CP ceramics,BCP, and TCP. In some embodiments, the scaffold or matrix is a hydrogelscaffold, a fibrous scaffold, a microsphere scaffold, apolymer-bioceramic composite scaffold, or an acellular scaffold.

In some embodiments, the scaffold or matrix is an osteoconductivematrix. Non-limiting examples of suitable osteoconductive matrixmaterials include, for example, collagen; homopolymers or copolymers ofglycolic acid, lactic acid, and butyric acid, including derivativesthereof and ceramics, hydroxyapatite, tricalcium phosphate, biphasiccalcium phosphate and other calcium phosphates, and calcium sulphates,or combinations thereof. Typically, osteoconductive matriciescontemplated herein include at least one of the previously listedmaterials. Other matrices useful in the present invention include, butare not limited to, biocomposite bone grafts, Kryptonite bone cement(Doctors Research Group, Oxford, Conn.), Vitoss, Vitoss BA, Orthoblend,Grafton, Arthrex, Allograft, Cadaverbone, Ostoset, Novabone, Augmatrix,Mastergraft, Hydroset, Pro-dense, Pro-stim, hydroset, (porous) tantalumbone graft, titanium mesh, titanium bone graft, and Genex bone graft.Combinations of these matrix materials also can be useful. Theosteoconductive matrix can also include a structural support such as acalcium salt, calcium sulfate, calcium phosphate, a calcium phosphatecement, hydroxyapatite, coralline based hydroyxapatite (HA), dicalciumphosphate, tricalcium phosphate (TCP), calcium carbonate, collagen,plaster of Paris, phosphophoryn, a borosilicate, a bioactive glass, abiocompatible ceramic, a calcium phosphate ceramic,polytetrafluoroethylene, sulfate salt, collagen, homopolymers orcopolymers of glycolic acid, lactic acid, and butyric acid, includingderivatives thereof and ceramics, hydroxyapatite, tricalcium phosphate,biphasic calcium phosphate and other calcium phosphates, and calciumsulphates. Other matrices useful in the present invention include, butare not limited to, biocomposite bone grafts, Kryptonite bone cement(Doctors Research Group, Oxford, Conn.), Vitoss, Vitoss BA, Orthoblend,Grafton, Arthrex, Allograft, Cadaverbone, Ostoset, Novabone, Augmatrix,Mastergraft, Hydroset, Pro-dense, Pro-stim, hydroset, (porous) tantalumbone graft, titanium mesh, titanium bone graft, Genex bone graftorhydrogel.

In some embodiments, the osteoconductive matrix comprises anosteoinductive agent and, optionally, a structural support. Theosteoinductive agent can be any agent that promotes bone formation. Insome embodiments, the osteoinductive agent is bone allograft, boneautograft, demineralized bone, or periodontal ligament cells.

C. Combination Therapy

In practicing the methods of the present invention, the pharmaceuticalcompositions can be used alone, or in combination with other therapeuticor diagnostic agents. Additionally, the medical devices described hereininclude the use of the compound of Formula I alone or in combinationwith an other therapeutic or diagnostic agents. The additional drugsused in the combination protocols of the present invention can beadministered separately or one or more of the drugs used in thecombination protocols can be administered together, such as in anadmixture. Where one or more drugs are administered separately, thetiming and schedule of administration of each drug can vary. The othertherapeutic or diagnostic agents can be administered at the same time asthe compounds of the present invention, separately or at differenttimes.

In some embodiments, a compound or composition as described herein(e.g., a compound or composition of Formula I) is administered incombination with one or more other therapeutic agents. When a compoundof the present invention and is combined with another agent, the two canbe co-administered or administered separately. Co-administrationincludes administering the other agent within 0.5, 1, 2, 4, 6, 8, 10,12, 16, 20, or 24 hours, as well as within 1 to 7 days (e.g., 1, 2, 3,4, 5, 6, or, 7 days), 1 to 4 weeks (e.g., 1, 2, 3, or 4 weeks), or 1 or18 months (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,17, or 18 months) of administering the compound of the presentinvention. Co-administration also includes administering the other agentand the compound of the present invention simultaneously, approximatelysimultaneously (e.g., within about 1, 5, 10, 15, 20, or 30 minutes, oron the same day, or on the same week, or on the same month of eachother), or sequentially in any order. In some embodiments,co-administration comprises administering another agent (e.g., anantiresorptive) for a period of time (e.g., weeks, months, or years),then administering a compound or composition of Formula I for a periodof time (e.g., days, weeks, months, or years), then administering theother agent (e.g., antiresorptive) either alone or in combination withthe compound or composition of Formula I. In some embodiments, the otheragent and the compound of the present invention can each be administeredonce a day, or two, three, or more times per day so as to provide thepreferred dosage level per day.

In some embodiments, co-administration can be accomplished byco-formulation, i.e., preparing a single pharmaceutical compositionincluding both a compound of the present invention and the secondtherapeutic agent (e.g., the antiresorptive agent). In otherembodiments, the compound of the present invention and the secondtherapeutic agent are formulated separately.

The one or more other therapeutic agents can be delivered by anysuitable means. The pharmaceutical preparation is preferably in unitdosage form. In such form the preparation is subdivided into unit dosescontaining appropriate quantities of the antiresorptive agent and/or thecompound of the present invention. The unit dosage form can be apackaged preparation, the package containing discrete quantities ofpreparation, such as packeted tablets, capsules, and powders in vials orampoules. Also, the unit dosage form can be a capsule, tablet, cachet,patch, or lozenge itself, or it can be the appropriate number of any ofthese in packaged form.

The one or more other therapeutic agents can be present in any suitableamount, and can depend on various factors including, but not limited to,weight and age of the subject, state of the disease, etc. Suitabledosage ranges for the one or more other therapeutic agents incombination with the a compound or composition of the present inventioninclude from about about 0.0001 ug to about 10,000 mg, or about 0.0001ug to about 1000 mg, or about 0.0001 ug to about 500 mg, or about 0.0001ug to about 1000 ug, 0.1 ug to about 10,000 mg, or about 0.1 ug to about1000 mg, or about 0.1 ug to about 500 mg, or about 0.1 ug to about 1000ug or about 1 ug to about 1000 mg, or about 1 ug to about 500 mg, orabout 1 ug to about 50 mg, or about 1 ug to about 1000 ug, or about 10ug to about 1000 mg, or about 10 ug to about 500 mg, or about 10 ug toabout 50 mg, or about 0.1 mg to about 10,000 mg, or about 1 mg to about1000 mg, or about 10 mg to about 750 mg, or about 25 mg to about 500 mg,or about 50 mg to about 250 mg. Suitable dosages for the one or moreother therapeutic agents in combination with a compound or compositionof the present invention, include about 0.01, 0.1, 1, 5, 10, 20, 30, 40,50, 60, 70, 80, 90, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000,1250, 1500, 1750 or 2000 mg.

The one or more other therapeutic agents and the compound or compositionof the present invention can be present in the compositions of thepresent invention in any suitable weight ratio, such as from about 1:100to about 100:1 (w/w), or about 1:50 to about 50:1, or about 1:25 toabout 25:1, or about 1:10 to about 10:1, or about 1:5 to about 5:1 (w/w)or about 1:1 (w/w). Other dosages and dosage ratios of theantiresorptive agent and the compound of the present invention aresuitable in the compositions and methods of the present invention.

The composition can also contain other compatible therapeutic agents.The compounds described herein can be used in combination with oneanother, with other active agents, or with adjunctive agents that maynot be effective alone, but may contribute to the efficacy of the activeagent.

In some embodiments, an individual to be treated according to a methodof the present invention is administered a compound or composition asdescribed herein (e.g., a compound or composition of Formula I, FormulaIa, Formula Ib, Formula Ic, or Formula Id as described herein) incombination or sequentially with an antiresorptive drug. Antiresorptivedrugs include those that slow or block the resorption of bone.Administration of a compound or composition as described herein and anantiresorptive drug can promote local bone growth and/or systemic bonegrowth. In some embodiments, the administration of a compound compoundor composition as described herein and an antiresorptive drug promotessystemic bone growth. Bone growth can be achieved by increasing bonemineral content, increasing bone density and/or growth of new bone. Inother embodiments, local application of the compound or composition asdescribed herein and an antiresorptive drug achieves systemic bonegrowth.

Antiresorptive drugs useful in the methods of the present inventioninclude, but are not limited to, denosumab, Prolia, a RankL inhibitor, abisphosphonate (e.g., Fosamax, denosumab, Prolia, Actonel, or Reclast,Alendronate, Bonviva™, Zometa™, olpadronate, neridronate, skelid,bonefos), a selective estrogen receptor modulator (SERM) or analog(e.g., Evista), calcitonin, a calcitonin analog (e.g., Miacalcic),parathyroid hormone, calcilytics, calcimimetics (e.g., cinacalcet),statins, anabolic steroids, lanthanum and strontium salts, and sodiumfluoride, Vitamin D or a Vitamin D analog, CatK inhibitor, prostaglandininhibitor, or phosphodiesterase inhibitor type E.

In some embodiments, the antiresorptive drug is denosumab.

Bisphosphonates useful in the methods of the present invention can beany suitable bisphosphonate. In some embodiments, the bisphosphonatesare nitrogenous, such as Pamidronate (APD, Aredia), Neridronate,Olpadronate, Alendronate (Fosamax), Ibandronate (Boniva), Risedronate(Actonel) and Zoledronate (Zometa). In other embodiments, thebisphosphonates are non-nitrogenous, such as Etidronate (Didronel),Clodronate (Bonefos, Loron) and Tiludronate (Skelid). One of skill inthe art will appreciate that other bisphosphonates are useful in thepresent invention.

SERMs useful in the methods of the present invention can be any suitableSERM. In some embodiments, the SERM can be clomifene, raloxifene,tamoxifen, toremifene, bazedoxifene, lasofoxifene or ormeloxifene. Oneof skill in the art will appreciate that other SERMs are useful in thepresent invention.

The antiresorptive drug can also be any suitable calcitonin analog orcathepsin K inhibitor. In some embodiments, calcitonin analogs useful inthe methods of the present invention include, but are not limited to,miacalcic. One of skill in the art will appreciate that other calcitoninanalogs are useful in the present invention.

Vitamin D analogs useful in the methods of the present invention can beany suitable Vitamin D analog. In some embodiments, Vitamin D analogsuseful in the methods of the present invention include, but are notlimited to, Vitamin D1 (molecular compound of ergocalciferol withlumisterol, 1:1), Vitamin D2 (ergocalciferol or calciferol), Vitamin D3(cholecalciferol), Vitamin D4 (22-dihydroergocalciferol) and Vitamin D5(sitocalciferol). One of skill in the art will appreciate that otherVitamin D analogs are useful in the present invention.

RankL inhibitors useful in the present invention include any compoundsthat inhibit the activity of RankL. For example, RankL inhibitorsinclude, but are not limited to, the human monoclonal antibody denosumabor prolia. One of skill in the art will appreciate that other RankLinhibitors are useful in the present invention.

In some embodiments, an individual to be treated according to a methodof the present invention is administered a compound or composition asdescribed herein (e.g., a compound or composition of Formula I, FormulaIa, Formula Ib, Formula Ic, or Formula Id as described herein) incombination or sequentially with an anabolic agent. Anabolic agentsinclude, but are not limited to, parathyroid hormone (PTH) or an analogthereof, sclerostin inhibitors, bone morphogenic protein (BMP) or a BMPagonist, a population of bone marrow stem cells, or a population ofmesenchymal stem cells.

In some embodiments, the anabolic agent is parathyroid hormone (PTH) oran analog thereof (e.g., teriparatide (Forteo). In some embodiments, theanabolic agent is a sclerostin antibody (Mab) inhibitor. In someembodiments, the BMP is selected from the group consisting of BMP2,BMP7, BMP4. In some embodiments, the BMP agonist is a compound describedin Vrij ens K, et al. PLoS One. 2013; 8(3):e59045, the contents of whichis incorporated by reference for all purposes. In some embodiments, theanabolic agent is a population of bone marrow stem cells. In someembodiments, the anabolic agent is a population of mesenchymal stemcells.

X. MEDICAL DEVICES

In some embodiments, the present invention provides a medical deviceformed from a structural support, wherein an implantable portion of thestructural support is adapted to be permanently implanted within asubject, wherein the implantable portion is attached to a bone, thestructural support bearing at least a partial coating including acompound of Formula I, as described herein (e.g., in Section III above).In some embodiments, the medical device is an orthopedic or periodontalmedical device.

Other aspects of the present invention are directed towards medicalimplants. Such medical devices and implants include, for example, theosteogenic devices and methods of using the same for repairingendochondral bone and osteochondral defects taught in US patentapplication publication No. 20060177475 to David Rueger et al.,published Aug. 10, 2006, as well as in issued U.S. Pat. Nos. 6,190,880,5,344,654, 5,324,819, 5,468,845, 6,949,251, 6,426,332 and 5,656,593, andU.S. Publication Nos. 2002/0169122, 2002/0187104, 2006/0252724 and2007/0172479, the subject matter of which is hereby incorporated byreference.

These medical devices generally provide a structural support having animplantable portion preferentially adapted to mechanically engage boneand/or cartilage as taught, for instance, in U.S. Publication No.2006/0178752 to Joseph Vaccarino III, et al., published Aug. 10, 2006,the subject matter of which is hereby incorporated by reference. Thesebone implants desirably comprise an active agent on at least a portionthereof. As shown by U.S. Publication No. 2006/0188542 to John DennisBobyn, et al., published Aug. 24, 2006, the subject matter of which ishereby incorporated by reference, the active agent is preferablyformulated to be locally deliverable to bone proximate the implant insustained-release or in at least a two-phased release scheme. In thelatter, a first phase rapidly releases a first quantity of the activeagent, and the second and subsequent phases gradually release a secondquantity of the active agent, whereby bone formation stimulated by theactive agent is modulated.

Medical devices such as bone implants feature implantable portionsbearing a compound or composition of present invention (e.g., a compoundor composition of Formula I) foster quicker and more complete boneformation in situ. The implantable portion of the medical device can bedesirable at least partially or totally covered or impregnated with acompound or composition of the present invention. In some embodiments,the medical device is externally coated with a compound or compositionas described herein. In some embodiments, the external coatingcompletely coats the implantable portion of the structural support. Insome embodiments, the structural support (e.g., matrix or scaffold)comprises a compound or composition as described herein within thesupport, i.e., internally. In some embodiments, the structural support(e.g., matrix or scaffold) comprises an external coating of a compoundor composition as described herein and also comprises the compound orcomposition within the support, i.e., internally.

Medical devices of the present invention include pins, rods, screws,plates, and orthopedic or dental implants. In some embodiments, themedical devices are made from material comprising metal, polymer, orceramic, or from combinations thereof. Metals useful for making medicaldevices of the present invention include, but are not limited to cobalt,chrome, chromium, stainless steel, titanium, titanium alloys, tantalum,trabecular metal. Polymers useful for making medical devices of thepresent invention include, but are not limited to ultra high molecularweight polyethylene or high density polyethylene. In some embodiments,carbon fiber is combined with polyethylene. Additional useful polymersare described below. Ceramics useful for making medical devices of thepresent invention include, but are not limited to aluminum oxide,calcium phosphates, hydroxyapatite, zirconium oxide, silicon oxide.

In some other embodiments, the implantable portion of the structuralsupport comprises an osteoconductive matrix. The matrix material can beconducive to bone growth. This can be desirable for materials such asteeth and artificial bone graft sections, and the like. Alternatively,when the implantable sections are load bearing and formed, e.g., ofstainless steel, these implantable sections can be desirable when formedwith a coating of a compound or composition of the present invention. Inthat event, it is desirable to also provide a separate matrix materialconducive to forming new bone growth.

In some embodiments, the matrix comprises particles of porous materials.The pores are preferred to be of a dimension to permit progenitor cellmigration into the matrix and subsequent differentiation andproliferation. In some embodiments, the pore size of the matrix is atleast 5 μm, e.g., at least 5, 10, 15, 20, 25, 30, 40, 50, 60, 70, 80,90, 100, 110, 115, 120, 125, 150, 175, 200, 250, 300, 400, 450, 500,550, 600, 650, 700, 750, 800, 850, 900, 950, 1000, 1250, 1500, 1750 or2000 μm. In some embodiments, the scaffold or matrix comprises a meshstructure, a foam structure, a sponge structure, or a fiber structure.

A scaffold or matrix for use in a device as described herein cancomprise a synthetic and/or biologic material. In some embodiments, thescaffold or matrix comprises a naturally occurring polymer, a syntheticbiodegradable polymer, a synthetic nonbiodegradable polymer, abioceramic, a bioglass, a bioactive glass, a biocompsite, orcombinations thereof. Natural and synthetic polymers, bioceramics, andbioglasses for use in scaffolds are known in the art. See, e.g.,Dhandayuthapani et al., International Journal of Polymer Science, volume2011, article ID 290602 (2011), incorporated by reference herein.Natural polymers include, but are not limited to, proteins (e.g., silk,collagen, gelatin, fibrinogen, elastin, keratin, actin, and myosin),polysaccharides (e.g., cellulose, amylose, dextran, chitin, chitosan,and glycosaminoglycans), and polynucleotides (e.g., DNA and RNA).Synthetic polymers include, but are not limited to, PLA, PGA, PLLA,PLGA, PCL, PLDLA, PDS, PGCL, PEA, PCA, PDLLA, PEU, and PBT. Bioceramicsand bioglasses include, but are not limited to, HAP, TCP, CP ceramics,BCP, and TCP. In some embodiments, the scaffold or matrix is a hydrogelscaffold, a fibrous scaffold, a microsphere scaffold, apolymer-bioceramic composite scaffold, or an acellular scaffold.

In some embodiments, suitable matrixes include those comprisingcomposite biomaterials having a sponge-like structure such as thosecontaining, e.g., phosphophoryn and/or collagen as taught in TakashiSaito's U.S. Publication No. 2006/0188544, published Aug. 24, 2006, thesubject matter of which is hereby incorporated by reference. Suchcoatings include, for example, the single and multilayer coatings taughtin U.S. Publication No. 2006/0204542 to Zongtao Zhang et al, publishedSep. 14, 2006, as well as those in U.S. Pat. Nos. 6,949,251, 5,298,852,5,939,039, and 7,189,263 and can be made by conventional methodsincluding the methods taught therein, the subject matter of which ishereby incorporated by reference.

In some embodiments, the matrix is an osteoconductive matrix. In someembodiments, the osteoconductive matrix includes an osteoinductive agentsuch as bone allograft, bone autograft, demineralized bone orperiodontal ligament cells or combinations thereof. In some otherembodiments, the osteoconductive matrix can be a calcium salt, calciumsulfate, biphasic calcium phosphate, calcium phosphate, a calciumphosphate cement, hydroxyapatite, coralline based hydroyxapatite (HA),dicalcium phosphate, tricalcium phosphate (TCP), calcium carbonate,collagen, plaster of Paris, phosphophoryn, a borosilicate, abiocompatible ceramic, a calcium phosphate ceramic,polytetrafluoroethylene, sulfate salt, borosilicate, bioactive glass,Mastergraft variant, Vitoss variant, cement hydrogel, or combinationsthereof. One of skill in the art will appreciate that otherosteconductive matrices and osteoinductive agents are useful in thepresent invention.

In some embodiments, the medical devices described herein include both aCompound of Formula I and an additional therapeutic agent. Suitableadditional therapeutic agents include the combinations discussed inSection IX. C., above. For example, the medical devices can Include acompound of Formula I in combination with an anabolic agent. In someembodiments, a medical device described herein include a compound ofFormula I in combination with a bone morphogenic protein (BMP) or a BMPagonist. In some embodiments, the BMP is selected from the groupconsisting of BMP2, BMP7, BMP4. In some embodiments, the BMP agonist isa compound described in Vrijens K, et al. PLoS One. 2013; 8(3):e59045,the contents of which is incorporated by reference for all purposes.

XI. ASSAY FOR IDENTIFICATION OF COMPOUNDS FOR TREATING BONE LOSS

Compounds useful in the methods of the present invention can beidentified via a variety of methods known to one of skill in the art.Several exemplary methods for identifying such antagonists are describedherein, including cell-based and in vitro techniques (Journal of Boneand Mineral Research 2006, 21(11), 1738-1749). A general method ofidentifying compounds involves evaluating the effects of antagonistcandidates on bone formation under controlled conditions. Preferablybone formation is determined using Dexa techniques on live animals oruCT on ex vivo samples. Preferred animals include rodents, morepreferred are primates. Femur, tibia and vertebrae bones areparticularly useful subjects for such study.

Briefly, the test animal is treated with a predetermined dose of acandidate compound. A control animal is treated with a control solution,preferably a non-irritating buffer solution or other carrier. When thecandidate compound is delivered in a carrier, the control solution isideally the carrier absent the candidate compound. Multiple doses of thecandidate compound can be applied to the test animal, preferablyfollowing a predetermined schedule of dosing. The dosing schedule can beover a period of days, e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25days or more; over a period of weeks, e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9,10 weeks or more; or other a period of months, e.g., 1, 2, 3, 4, 5, 6,7, 8, 9, 10 months or more.

In an exemplary embodiment, localized administration in situ of acandidate compound can be made into a test animal, with a control animalreceiving an equal volume of control solution without the candidatecompound. Suitable dosage will depend on the nature of the particularcandidate compound being tested. By way of example, in dosing it shouldbe noted that systemic administration (e.g., by oral or injection, e.g.,intravenously, subcutaneously or intramuscularly), can also be used.Dosing performed by nebulized inhalation, eye drops, or oral ingestionshould be at an amount sufficient to produce blood levels of thecandidate compound similar to those reached using systemic injection.The amount of candidate compound that can be delivered by nebulizedinhalation, eye drops, or oral ingestion to attain these levels isdependent upon the nature of the inhibitor used and can be determined byroutine experimentation.

Once the dosing schedule has been completed, both test and controlanimals are examined to determine the quantity of bone formationpresent. This can be accomplished by any suitable method, but ispreferably performed on live animals to analyze the bone mineralcontent. Methods for microCT examination of bones in animals are wellknown in the art. A candidate compound suitable for use in promotingbone formation is identified by noting a significant increase in boneformation in the test animal when compared to the control animal. Insome embodiments, a candidate compound is identified as suitable for usein promoting bone formation if the amount of bone formation in the testbone(s) of the test animal is at least 0.5%, 1, 3, 5, 6, 7, 8, 9, 10,11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 22, 24, 26, 28, 30, 40, 50, 60,70, 80, 90, 100, 200, 300, 400, 500, 600, 700, 800, 900 or 1000% or moreas compared to the comparable bone(s) of the control animal. In someembodiments, bone formation is increased by at least 3%, at least 5%, atleast 7%, at least 10%, at least 12%, at least 14%, at least 16%, atleast 18%, at least 20%, at least 30%, at least 40%, at least 50% ormore as compared to the control animal. Where necessary, levels of boneformation can be calculated by determining the volume of bone formationpresent in each animal. Calculations can be performed by constructing a3dimensional image of the bone formation and calculating the volume fromthe image with the aid of e.g., histomorphometry.

An example of the molecular modeling system described generally aboveconsists of the CHARMm and QUANTA programs, Polygen Corporation,Waltham, Mass. CHARMm performs the energy minimization and moleculardynamics functions. QUANTA performs the construction, graphic modelingand analysis of molecular structure. QUANTA allows interactiveconstruction, modification, visualization, and analysis of the behaviorof molecules with each other.

Compounds may also be identified using a process known as computer, ormolecular modeling, which allows visualization of the three-dimensionalatomic structure of a selected molecule and the rational design of newcompounds that will interact with the molecule. The three-dimensionalconstruct typically depends on data from x-ray crystallographic analysesor NMR imaging of the selected molecule. The molecular dynamics requireforce field data. The computer graphics systems enable prediction of howa new compound will link to the target molecule and allow experimentalmanipulation of the structures of the compound and target molecule toperfect binding specificity. Prediction of what the molecule-compoundinteraction will be when small changes are made in one or both requiresmolecular mechanics software and computationally intensive computers,usually coupled with user friendly, menu driven interfaces between themolecular design program and the user.

XII. PARTICULAR EMBODIMENTS OF THE PRESENT DISCLOSURE

Embodiment 1. A compound according to Formula I:

or a salt, hydrate, prodrug, or isomer thereof, wherein

X is selected from CR^(3b) and N, wherein N is optionally oxidized tothe corresponding N-oxide;

Y is selected from CR^(3c) and N, wherein N is optionally oxidized tothe corresponding N-oxide;

Z is selected from CR^(3d) and N, wherein N is optionally oxidized tothe corresponding N-oxide,

provided that at least one of X, Y, and Z is N or the correspondingN-oxide;

A is

R^(N) is selected from the group consisting of heterocyclyl andheteroaryl, wherein

the heterocyclyl moiety is selected from monocyclic, fused bicyclic, andbridged cyclic, the monocyclic heterocyclyl comprising from 4 to 7 ringmembers, the fused bicyclic and bridged bicyclic heterocyclyl comprisingfrom 7 to 10 ring members, each heterocyclyl moiety having from 1 to 3heteroatoms as ring members selected from N, O, and S, wherein eachheterocyclyl moiety comprises at least one nitrogen atom as a ringmember and is optionally substituted with from 1 to 3 R⁶ moieties,

the heteroaryl moiety comprises from 5 to 10 ring members, wherein atleast one ring member is a nitrogen atom and is optionally substitutedwith from 1 to 3R⁶ moieties,

each R², R^(3b), R^(3c) and R^(3d) is independently selected from thegroup consisting of H, halogen, C₁₋₆ alkyl, C₁₋₆ haloalkyl, C₂₋₆alkenyl, C₂₋₆ alkynyl, C₁₋₆ alkoxy, C₁₋₆ haloalkoxy, C₁₋₆ alkyl-OH,—O—C₁₋₆ alkyl-OH, C₃₋₆ cycloalkyl-C₁₋₄alkoxy, and —OH;

R⁶ is selected from the group consisting of —OH, C₁₋₃ alkyl, C₁₋₃alkyl-OH, —O—C₁₋₃ alkyl, C₃₋₄ heteroalkyl, C₁₋₃ haloalkyl, —O—C₁₋₃haloalkyl, halogen, and oxo.

Embodiment 2. The compound according to embodiment 1, having the FormulaIa, Ib, Ic, or Id:

Embodiment 3. The compound of embodiment 1 or 2, wherein R² is selectedfrom the group consisting of H, halogen, C₁₋₆ alkyl, C₁₋₆ haloalkyl,C₁₋₆ alkoxy, and C₁₋₆ haloalkoxy.

Embodiment 4. The compound of embodiment 1 or 2, wherein R² is selectedfrom the group consisting of halogen, C₁₋₆ alkyl, C₁₋₆ haloalkyl, andC₁₋₆ alkoxy.

Embodiment 5. The compound of embodiment 4, wherein R² is C₁₋₆alkyl orC₁₋₆ haloalkyl.

Embodiment 6. The compound of embodiment 5, wherein R² is CH₃ or CF₃.

Embodiment 7. The compound of embodiment 6, wherein R² is CH₃.

Embodiment 8. The compound of embodiment 6, wherein R² is CF₃.

Embodiment 9. The compound of any one of embodiments 1 to 8, wherein

each R^(3b), R^(3c) and R^(3d), when present, is independently selectedfrom the group consisting of H, halogen, C₁₋₆ alkyl, C₁₋₆ haloalkyl,C₁₋₆ alkoxy, C₁₋₆ haloalkoxy.

Embodiment 10. The compound of embodiment 9, wherein

each R^(3b), R^(3c) and R^(3d), when present, is independently selectedfrom the group consisting of H, halogen, and C₁₋₆ alkoxy.

Embodiment 11. The compound of embodiment 10, wherein

each R^(3b), R^(3c) and R^(3d), when present, is independently selectedfrom the group consisting of H, F, and methoxy.

Embodiment 12. The compound of any one of embodiments 1 to 8, wherein

R^(3c), when present, is methoxy.

Embodiment 13. The compound of any of embodiments 1 to 11, wherein

R^(N) i s heterocyclyl or heteroaryl.

Embodiment 14. The compound of embodiment 13, wherein R^(N) isheterocyclyl.

Embodiment 15. The compound of embodiment 14, wherein R^(N) is amonocyclic heterocyclyl.

Embodiment 16. The compound of embodiment 13, wherein R^(N) is

Embodiment 17. The compound of embodiment 1, wherein

R² is selected from the group consisting of H, C₁₋₆alkyl, and C₁₋₆haloalkyl,

R^(3c), if present, is H or C₁₋₆ alkoxy;

R^(3b) or R^(3d), if present, is H or halogen; and

R^(N) is heterocyclyl or heteroaryl.

Embodiment 18. The compound of embodiment 17, wherein

R² is H or C₁₋₆ haloalkyl;

R^(3c), if present, is C₁₋₆ alkoxy;

R^(3b) or R^(3d), if present, is H or halogen; and

R^(N) is

Embodiment 19. The compound of embodiment 2, wherein

R² is C₁₋₆ alkyl or C₁₋₆ haloalkyl;

R^(3b), if present, is H or halogen;

R^(3c) is C₁₋₆ alkoxy; and

R^(N) is heterocyclyl or heteroaryl.

Embodiment 20. The compound of embodiment 19, wherein

R² is C₁₋₆ haloalkyl;

R^(3b), if present, is H or halogen;

R^(3c) is C₁₋₆ alkoxy; and

R^(N) is

Embodiment 21. The compound of embodiment 20, wherein

R² is CF₃; and

R^(3c) is methoxy.

Embodiment 22. The compound of embodiment 1, selected from the groupconsisting of

or salts, hydrates, or prodrugs thereof.

Embodiment 23. A formate salt of a compound of any one of embodiments 1to 22.

Embodiment 24. A sulfate salt of a compound of any of embodiments 1 to22.

Embodiment 25. A citrate salt of a compound of any one of embodiments 1to 22.

Embodiment 26. A hydrochloride salt of a compound of any one ofembodiments 1 to 22.

Embodiment 27. A prodrug of a compound of any one of embodiments 1 to22.

Embodiment 28. A pharmaceutical composition comprising a compound of anyof embodiments 1 to 27 and a pharmaceutically acceptable excipient.

Embodiment 29. A method of promoting bone formation a subject in needthereof, comprising administering to the subject a therapeuticallyeffective of a compound of any one of embodiments 1 to 28, therebypromoting bone formation in the subject.

Embodiment 30. The method of embodiment 29, wherein the bone formationis promoted at a surgical site of injury or localized condition.

Embodiment 31. The method of embodiment 30, wherein the bone formationis promoted at a surgical site selected from the group consisting of abone fracture and weakened bone.

Embodiment 32. The method of embodiment 30, wherein the subject is inneed of a spinal fusion, arthrodesis or an orthopedic or periodontalsynthetic bone graft or implant.

Embodiment 33. The method of embodiment 29, wherein the bone formationis systemic.

Embodiment 34. The method of any of embodiments 29-33, wherein thesubject has a low bone mass/density condition, a bone fracture, orperiodontal disease.

Embodiment 35. The method of embodiment 34, wherein the low bone masscondition is selected from osteoporosis, osteopenia, osteogenesisimperfecta (OI), osteoporosis-pseudoglioma syndrome (OPPG), andsecondary low bone condition.

Embodiment 36. The method of embodiment 35, wherein the low bone masscondition is selected from the group consisting of osteoporosis,osteopenia, and osteoporosis-pseudoglioma syndrome (OPPG).

Embodiment 37. The method of any of embodiments 29-36, furthercomprising administering to the subject an osteoconductive matrix.

Embodiment 38. The method of embodiment 37, wherein the osteoconductivematrix comprises an osteoinductive agent selected from the groupconsisting of bone allograft, bone autograft, and periodontal ligamentcells.

Embodiment 39. The method of embodiment 37, wherein the osteoconductivematrix comprises a calcium salt, calcium sulfate, calcium phosphate, acalcium phosphate cement, hydroxyapatite, coralline based hydroyxapatite(HA), dicalcium phosphate, tricalcium phosphate (TCP), calciumcarbonate, collagen, plaster of Paris, phosphophoryn, a borosilicate, abiocompatible ceramic, a calcium phosphate ceramic, demineralized bonematrix, biphasic calcium phosphate, biocomposite, tantalum, titanium,polytetrafluoroethylene, sulfate salt, hydrogel, bioglass, orcombinations thereof.

Embodiment 40. The method of embodiment 37, wherein the osteoconductivematrix comprises a calcium salt, calcium sulfate, calcium phosphate, acalcium phosphate cement, hydroxyapatite, coralline based hydroyxapatite(HA), dicalcium phosphate, tricalcium phosphate (TCP), calciumcarbonate, collagen, plaster of Paris, phosphophoryn, a borosilicate, abiocompatible ceramic, a calcium phosphate ceramic, demineralized bonematrix, biphasic calcium phosphate, biocomposite, tantalum, titanium,polytetrafluoroethylene, sulfate salt, or hydrogel.

Embodiment 41. The method of any of embodiments 29-40, wherein thecompound is administered sequentially or in combination with anantiresorptive drug.

Embodiment 42. The method of embodiment 41, wherein the compound isadministered to a patient who is being treated with the antiresorptivedrug or has previously been treated with the antiresorptive drug.

Embodiment 43. The method of embodiment 41, wherein the antiresorptivedrug is selected from the group consisting of denosumab, prolia, a RankLinhibitor, a bisphosphonate, a selective estrogen receptor modulator(SERM), calcitonin, a calcitonin analog, Vitamin D, a Vitamin D analog,and a cathepsin K inhibitor.

Embodiment 44. The method of embodiment 41, wherein the antiresorptivedrug is denosumab.

Embodiment 45. The method of embodiment 41, wherein the antiresorptivedrug is administered systemically.

Embodiment 46. The method of embodiment 41, wherein the antiresorptivedrug is administered locally.

Embodiment 47. The method of any of embodiments 29-46, furthercomprising administering an anabolic agent.

Embodiment 48. A medical device comprising a structural support, whereinan implantable portion of the structural support is adapted to bepermanently implanted within a subject, wherein the implantable portionis attached to a bone, the structural support bearing at least a partialexternal coating comprising a compound of any one of embodiments 1 to28.

Embodiment 49. A method of treating bone loss in a subject in needthereof, comprising administering to the subject a therapeuticallyeffective of a compound of any one of embodiments 1 to 28 in series orin combination with an antiresorptive agent, thereby treating bone lossin a subject

XIII. EXAMPLES Example 14-(2-(1-(Trifluoromethyl)-9H-pyrrolo[2,3-c:5,4-c]dipyridin-9-yl)ethyl)morpholinehydrochloride salt

A round-bottom flask was charged with 3-bromo-2-trifluoromethylpyridine(500 mg, 2.21 mmol) and 3-amino-4-chloropyridine (298 mg, 2.32 mmol).The flask was flushed with Ar, and PhMe (5 mL) was added. To theresulting solution were added Cs₂CO₃ (866 mg, 2.65 mmol), X-Phos (80 mg,0.16 mmol), and Pd(OAc)₂ (25 mg, 0.11 mmol), in that order. The flaskwas equipped with a Liebig condenser and the mixture was degassed andstirred overnight at 110° C. under Ar. The mixture was allowed to cool,diluted with EtOAc, and washed once with water, once with brine, dried(MgSO₄), and evaporated. Flash chromatography over SiO₂ (40 g) using30-100% EtOAc-hexanes (gradient elution) afforded4-chloro-N-(2-(trifluoromethyl)pyridin-3-yl)pyridin-3-amine (314 mg,52%).

A flask was charged with4-chloro-N-(2-(trifluoromethyl)pyridin-3-yl)pyridin-3-amine (314 mg,1.15 mmol) and DMA (10 mL) was added, followed by K₂CO₃ (317 mg, 2.30mmol). The mixture was then degassed and placed under Ar atmosphere.t-Bu₃P-HBF₄ (85 mg, 0.30 mmol) followed by Pd(OAc)₂ (26 mg, 0.12 mmol)were added, the mixture was degassed again, placed under Ar, and heatedat 130° C. overnight. The mixture was then re-charged with additionalportions of t-Bu₃P-HBF₄ (85 mg, 0.30 mmol) and Pd(OAc)₂ (26 mg, 0.12mmol), and stirred at 130° C. overnight again. The mixture was allowedto cool, diluted with EtOAc, washed once with water, once with brine,dried (MgSO₄), and evaporated. Flash chromatography over SiO₂ (24 g)using 60-100% EtOAc-hexanes afforded1-(trifluoromethyl)-9H-pyrrolo[2,3-c:5,4-c′]dipyridine (100 mg, 37%).

4-(2-chloroethyl)morpholine HCl (94.1 mg, 0.510 mmol) was added to astirred solution of1-(trifluoromethyl)-9H-pyrrolo[2,3-c:5,4-c′]dipyridine(100 mg, 0.420mmol) in DMF (5 mL). NaH (60% in oil, 100 mg, 2.52 mmol) was added inone portion, the flask was flushed with Ar, and the mixture was heatedat 60° C. overnight with stirring. The mixture was allowed to cool toroom temperature, diluted with EtOAc, washed once with water, once withbrine, dried (MgSO₄), and evaporated. Flash chromatography of theresidue over SiO₂ (12 g) using 50-100% EtOAc-hexanes, followed by 50%MeOH-EtOAc, afforded compound4-(2-(1-(trifluoromethyl)-9H-pyrrolo[2,3-c:5,4-c′]dipyridin-9-yl)ethyl)morpholine(14 mg, 10%) and oxidized compound9-(2-morpholinoethyl)-8-(trifluoromethyl)-9H-pyrrolo[2,3-c:5,4-c′]dipyridine2-oxide (10 mg, 6%).

Characterization for4-(2-(1-(trifluoromethyl)-9H-pyrrolo[2,3-c:5,4-c′]dipyridin-9-yl)ethyl)morpholine:¹H NMR (CDCl₃, 400 MHz) δ 9.16 (s, 1H), 8.63 (d, 1H, J=5.2 Hz), 8.59 (d,1H, J=4.8 Hz), 8.25 (d, 1H, J=5.2 Hz), 8.04 (dd, 1H, J=5.2, 0.8 Hz),4.74 (t, 2H, J=7.6 Hz), 3.69 (t, 4H, J=4.8 Hz), 2.79 (t, 2H, J=7.6 Hz),2.54 (t, 4H, J=4.8 Hz).

HCl (2 M in Et₂O, 10 eq) was added via syringe to a stirred solution of4-(2-(1-(trifluoromethyl)-9H-pyrrolo[2,3-c:5,4-c′]dipyridin-9-yl)ethyl)morpholineor oxidized compound9-(2-morpholinoethyl)-8-(trifluoromethyl)-9H-pyrrolo[2,3-c:5,4-c′]dipyridine2-oxide in CH₂Cl₂ (1 mL). Stirring was continued for 5 min and then thevolatiles were removed in-vacuo. The residue was purified by triturationusing 80% CH₂Cl₂-hexanes to afford4-(2-(1-(trifluoromethyl)-9H-pyrrolo[2,3-c:5,4-c′]dipyridin-9-yl)ethyl)morpholinehydrochloride salt or oxidized compound9-(2-morpholinoethyl)-8-(trifluoromethyl)-9H-pyrrolo[2,3-c:5,4-c′]dipyridine2-oxide hydrochloride salt in quantitative yield.

Characterization for4-(2-(1-(trifluoromethyl)-9H-pyrrolo[2,3-c:5,4-c′]dipyridin-9-yl)ethyl)morpholinehydrochloride salt: ¹H NMR (DMSO-d₆, 400 MHz) δ 12.00 (s, 1H), 9.88 (s,1H), 8.88 (d, 1H, J=4.8 Hz), 8.80 (s, 2H), 8.74 (d, 1H, J=4.8 Hz), 5.15(t, 2H, J=8.4 Hz), 4.04 (m, 2H), 3.86 (m, 2H), 3.59 (m, 2H), 3.50 (m,2H), 3.23 (m, 2H). LCMS m/z 351.2 ([M+H]⁺, C₁₇H₁₈F₃N₄O requires 351.2).

Example 29-(2-Morpholinoethyl)-8-(trifluoromethyl)-9H-pyrrolo[2,3-c:5,4-c′]dipyridine2-oxide hydrochloride salt

Free base: ¹H NMR (CDCl₃, 400 MHz) δ 9.94 (s, 1H), 8.54 (d, 1H, J=5.2Hz), 8.03 (d, 1H, J=5.2 Hz), 7.24 (d, 1H, J=7.2 Hz), 6.93 (d, 1H, J=7.2Hz), 4.27 (t, 2H, J=6.4 Hz), 3.68 (t, 4H, J=4.4 Hz), 2.78 (t, 2H, J=6.4Hz), 2.54 (t, 4H, J=4.4 Hz).

HCl Salt: ¹H NMR (DMSO-d₆, 400 MHz) δ 12.84 (s, 1H), 10.24 (bs, 1H),8.48 (d, 1H, J=5.2 Hz), 8.43 (d, 1H, J=5.2 Hz), 7.59 (d, 1H, J=7.2 Hz),7.28 (d, 1H, J=7.2 Hz), 4.51 (m, 2H), 3.99 (m, 2H), 3.62 (m, 6H), 3.17(m, 2H). LCMS m/z 367.2 ([M+H]⁺, C₁₇H₁₈F₃N₄O₂ requires 367.2).

Example 34-(2-(2-Methoxy-8-(trifluoromethyl)-9H-pyrrolo[2,3-b:5,4-c′]dipyridin-9-yl)ethyl)morpholinehydrochloride salt

To a 0° C. solution of 6-methoxypyridin-2-amine (5.0 g, 40 mmol) inCHCl₃ (150 ml) was added portionwise NCS (5.35 g, 40 mmol). The reactionsolution was stirred at room temperature for 3 days and then dilutedwith CH₂Cl₂, washed with water, NaHCO₃ (sat), brine, dried over MgSO₄and concentrated. Product was purified by silica chromatography using a90% hexanes/10% EtOAc to 50% hexanes/50% EtOAc gradient to give3-chloro-6-methoxypyridin-2-amine (4.8 g, 75%).

To a dry tube was added 3-bromo-2-trifluoromethylpyridine (500 mg, 2.2mmol), cesium carbonate (866 mg, 2.7 mmol), X-Phos (80 mg, 0.16 mmol),Pd(OAc)₂ (25 mg, 0.1 mmol) and 3-chloro-6-methoxypyridin-2-amine (370mg, 2.3 mmol). The reaction solution was diluted with toluene (5 ml),degassed and stirred at 120° C. overnight and then cooled to roomtemperature, diluted with EtOAc, washed with water, brine, dried overMgSO₄ and concentrated. Product was purified by silica chromatographyusing a 80% Hexanes/20% EtOAc to 100% EtOAc gradient to give3-chloro-6-methoxy-N-(2-(trifluoromethyl)pyridin-3-yl)pyridin-2-amine(588 mg, 88%).

To a dry tube was added the3-chloro-6-methoxy-N-(2-(trifluoromethyl)pyridin-3-yl)pyridin-2-amine(588 mg, 1.9 mmol), potassium carbonate (536 mg, 3.9 mmol) and DMA (20ml). The reaction was degassed and (t-Bu₃)PHBF₄ (113 mg, 0.39 mmol) andPd(OAc)₂ (45 mg, 0.19 mmol) were introduced. The reaction was stirred at120° C. overnight. An additional aliquot of catalyst was added and thereaction stirred at 120° C. overnight then cooled to room temperature,diluted with EtOAc, washed with water, brine, dried over MgSO₄ andconcentrated. The product was purified by silica chromatography using a85% hexanes/15% EtOAc to 50% hexanes/50% EtOAc gradient. The product wasrepurified by reverse phase chromatography on C₁₈ column using a 50%ACN/50% water (0.1% FA) to 90% ACN/10% water (0.1% FA) gradient. As theDes-chloro material was still present, the product was again repurifiedby HPLC C₁₈ column using a 10% ACN/90% water (0.1% FA) to 90% ACN/10%water (0.1% FA) gradient to give2-methoxy-8-(trifluoromethyl)-9H-pyrrolo[2,3-b:5,4-c′]dipyridine (47 mg,9%).

Characterization for2-methoxy-8-(trifluoromethyl)-9H-pyrrolo[2,3-b:5,4-c′]dipyridine: ¹H NMR(CDCl₃, 400 MHz) δ 8.47 (d, 1H, J=4.8 Hz), 8.23 (dd, 1H, J=8.4, 0.8 Hz),7.98 (d, 1H, J=4.8 Hz), 6.74 (dd, 1H, J=8.4, 0.8 Hz), 4.76 (t, 2H, J=7.6Hz), 4.07 (s, 3H), 3.69 (t, 4H, J=4.8 Hz), 2.77 (t, 2H, J=7.6 Hz), 2.60(t, 4H, J=4.4 Hz).

To a solution of2-methoxy-8-(trifluoromethyl)-9H-pyrrolo[2,3-b:5,4-c′]dipyridine (47 mg,0.18 mmol) in DMF (3 ml) was added 4-(2-chloroethyl)morpholinehydrochloride (66 mg, 0.35 mmol) followed by sodium hydride (60% in oil,42 mg, 1.1 mmol). The solution was stirred at 60° C. for overnight thencooled to room temperature, quenched with NaHCO₃ (sat) and diluted withEtOAc. The crude product was washed with NaHCO₃ (sat), brine, dried overMgSO₄ and concentrated. The product was purified by silicachromatography using a 70% hexanes/30% EtOAc to 100% EtOAc gradient togive4-(2-(2-Methoxy-8-(trifluoromethyl)-9H-pyrrolo[2,3-b:5,4-c═]dipyridin-9-yl)ethyl)morpholine(42 mg, 63%). This product was then diluted with CH₂Cl₂ and 1 ml of 4MHCl in dioxane was added and stirred 10 min then evaporated to dryness.Trituration from CH₂Cl₂/hexanes gave the4-(2-(2-Methoxy-8-(trifluoromethyl)-9H-pyrrolo[2,3-b:5,4-c]dipyridin-9-yl)ethyl)morpholinehydrochloride salt in quantitative yield.

Characterization for4-(2-(2-Methoxy-8-(trifluoromethyl)-9H-pyrrolo[2,3-b:5,4-c′]dipyridin-9-yl)ethyl)morpholinehydrochloride salt: ¹H NMR (DMSO-d₆, 400 MHz) δ 11.54 (s, 1H), 8.69 (d,1H, J=8.4 Hz), 8.53 (d, 1H, J=5.2 Hz), 8.46 (d, 1H, J=4.8 Hz), 6.91 (d,1H, J=8.4 Hz), 4.98 (m, 2H), 4.09 (s, 3H), 4.02 (d, 2H, J=12.4 Hz), 3.84(m, 2H), 3.65 (d, 2H, J=10.4 Hz), 3.45 (m, 2H), 3.22 (m, 2H). LCMS m/z381.2 ([M+H]⁺, C₁₈H₂₀F₃N₄O₂ requires 381.2).

Example 44-(2-(3-Methoxy-6-(trifluoromethyl)-5H-pyrrolo[2,3-c:4,5-c′]dipyridin-5-yl)ethyl)morpholinehydrochloride salt

A flask was charged with 5-chloro-2-methoxypyridin-4-amine HCl salt(0.6065 g, 3.109 mmol), 3-bromo-2-trifluoromethylpyridine (3) (0.77 g,3.41 mmol), Cs₂CO₃ (2.53 g, 7.77 mmol), X-Phos ligand (0.22 g, 0.46mmol), and Pd(OAc)₂ (0.14 g, 0.62 mmol). The flask was equipped with acondenser, flushed with Ar, and m-xylene (8.8 mL) was added. The mixturewas degassed, placed under Ar, and refluxed overnight with stirring. Themixture was allowed to cool and, diluted with water and EtOAc, andfiltered through Celite (using EtOAc to wash the filter-cake). Theaqueous layer was extracted once with EtOAc, and the combined organicextracts were washed once with water, once with brine, dried (Na₂SO₄),and evaporated. Purification of the residue by flash chromatography gaveimpure material (as an inseparable mixture of starting aniline and thedesired product). The mixture was separated by flash chromatography overreverse phase C-18 silica, using Biotage SNAP cartridge KP-C18-HS (60 g)and eluting with 30-95% MeCN—H₂O (gradient elution), to affordN-(5-chloro-2-methoxypyridin-4-yl)-2-(trifluoromethyl)pyridin-3-amine(0.3069 g, 33%).

A microwave flask was charged with t-Bu₃P-HBF₄ (59 mg, 0.20 mmol), K₂CO₃(0.35 g, 2.5 mmol), Pd(OAc)₂ (34 mg, 0.15 mmol), and PivOH (21 mg, 0.20mmol). The flask was capped, flushed with Ar, andN-(5-chloro-2-methoxypyridin-4-yl)-2-(trifluoromethyl)pyridin-3-amine(0.3069 g, 1.011 mmol) in DMA (4 mL) was added via syringe. Ar wasbubbled through the solution for 5 min, with stirring, before heating inthe microwave at 164° C. for 2 h, with stirring. The mixture was allowedto cool, diluted with EtOAc, and filtered through Celite, using EtOAc towash the filter-cake. The mixture was then washed twice with brine,dried (Na₂SO₄), and evaporated. Purification of the residue by flashchromatography over SiO₂ (40 g) using 5-40% EtOAc-hexanes (gradientelution) afforded2-methoxy-8-(trifluoromethyl)-9H-pyrrolo[2,3-b:5,4-c′]dipyridine (34.2mg, 13%).

NaH (60% in oil, 30 mg, 0.75 mmol) was added in one portion to a stirredsolution of2-methoxy-8-(trifluoromethyl)-9H-pyrrolo[2,3-b:5,4-c′]dipyridine (34 mg,0.127 mmol), 4-(2-chloroethyl)morpholine hydrochloride (48 mg, 0.25mmol), and TBAI (5 mg, 0.01 mmol) in DMF (1.8 mL). The flask was flushedwith N₂ and heated at 60° C. overnight with stirring. The next day themixture was allowed to cool to room temperature, diluted with EtOAc,washed once with water, once with brine, dried (Na₂SO₄), and evaporated.Purification of the residue by flash chromatography over SiO₂ (12 g)using 20-100% EtOAc-hexanes (gradient elution) afforded4-(2-(3-methoxy-6-(trifluoromethyl)-5H-pyrrolo[2,3-c:4,5-c′]dipyridin-5-yl)ethyl)morpholine(33 mg, 69%).

Characterization for4-(2-(3-methoxy-6-(trifluoromethyl)-5H-pyrrolo[2,3-c:4,5-c′]dipyridin-5-yl)ethyl)morpholine:¹H NMR (CDCl₃, 400 MHz) δ 8.98 (s, 1H), 8.53 (d, 1H, J=5.2 Hz), 8.11 (d,1H, J=5.2 Hz), 6.79 (s, 1H), 4.52 (t, 2H, J=7.6 Hz), 4.07 (s, 3H), 3.72(t, 4H, J=4.4 Hz), 2.72 (t, 2H, J=7.6 Hz), 2.56 (t, 4H, J=4.4 Hz).

HCl (0.2 M in Et₂O, 0.42 mL, 0.084 mmol) was added via syringe to astirred solution of4-(2-(3-methoxy-6-(trifluoromethyl)-5H-pyrrolo[2,3-c:4,5-c′]dipyridin-5-yl)ethyl)morpholine(16 mg, 0.042 mmol) in CH₂Cl₂ (1 mL). The mixture was stirred for 10 minand the volatiles were removed in-vacuo to obtain an off-white solid.The solid was triturated with 1:1 Et₂O-hexanes (ca. 2 mL) to afford4-(2-(3-methoxy-6-(trifluoromethyl)-5H-pyrrolo[2,3-c:4,5-c′]dipyridin-5-yl)ethyl)morpholinehydrochloride salt (17.5 mg, quantitative) as a white solid.

Characterization for4-(2-(3-methoxy-6-(trifluoromethyl)-5H-pyrrolo[2,3-c:4,5-c′]dipyridin-5-yl)ethyl)morpholinehydrochloride salt: ¹H NMR (DMSO-d₆, 400 MHz) δ 11.83 (s, 1H), 9.27 (s,1H), 8.58 (d, 1H, J=5.2 Hz), 8.55 (d, 1H, J=4.8 Hz), 7.43 (s, 1H), 4.88(t, 2H, J=8.4 Hz), 4.01 (s, 3H), 3.82 (d, 2H, J=11.6 Hz), 3.70 (m, 2H),3.59 (d, 2H, J=11.2 Hz), 3.35 (m, 2H), 3.18 (m, 2H). LCMS m/z 381.2([M+H]⁺, C₁₈H₂₀F₃N₄O₂ requires 381.2).

Example 54-(2-(2-Methoxy-8-(trifluoromethyl)-9H-pyrido[4′,3′:4,5]pyrrolo[2,3-d]pyrimidin-9-yl)ethyl)morpholine

MeONa (25% in MeOH, 3.3 mL, 14.6 mmol) was added to a stirred solutionof 2,5-dichloropyrimidin-4-amine (2 g, 12.2 mmol) in methanol (40 mL).The mixture was stirred at 50° C. for 4 h with protection from moisture.The mixture was then allowed to cool to room temperature and quenched byaddition of saturated NH₄Cl_((aq)). EtOAc was added and the organic waswashed once with NaHCO_(3(aq)), once with brine, and dried (MgSO₄).Evaporation of the solvent provided 6-amino-5-chloro-2-methoxypyrimidinewithout further purification.

A microwave flask was charged with 6-amino-5-chloro-2-methoxypyrimidine(404 mg, 2.53 mmol) and 3-bromo-2-trifluoromethylpyridine (500 mg, 2.21mmol). The flask was flushed with Ar and DMF (3 mL) was added viasyringe. Cs₂CO₃ (866 mg, 2.66 mmol) followed by X-Phos ligand (80 mg,0.16 mmol) were added. The solution was degassed, then Pd(OAc)₂ (25 mg,0.11 mmol) was added and the flask was re-flushed with Ar. The mixturewas heated at 160° C. in the microwave (Biotage) for 2 h, allowed tocool, and then diluted with EtOAc, washed once with water, once withbrine, and dried (MgSO₄). Flash chromatography over SiO₂ (40 g) using20-80% EtOAc-hexanes (gradient elution) afforded5-chloro-2-methoxy-N-(2-(trifluoromethyl)pyridin-3-yl)pyrimidin-4-amine(120 mg, 18%).

A microwave flask was charged with5-chloro-2-methoxy-N-(2-(trifluoromethyl)pyridin-3-yl)pyrimidin-4-amine(120 mg, 0.394 mmol) and DMA (5 mL) was added, followed by K₂CO₃ (109mg, 0.788 mmol). The mixture was then degassed and placed under Aratmosphere. t-Bu₃P-HBF₄ (22.8 mg, 0.0788 mmol) followed by Pd(OAc)₂ (8.8mg, 0.0394 mmol) were added, the mixture was degassed again, placedunder Ar, and heated at 130° C. overnight. At this point the conversionwas low (LCMS) and so the mixture was re-charged with additionalportions of t-Bu₃P-HBF₄ ligand (22.8 mg, 0.0788 mmol) and Pd(OAc)₂catalyst (8.8 mg, 0.0394 mmol) and heated in the microwave (Biotage) at160° C. for 1.5 h. At this point the conversion was ca. 50% (LCMS) andthe mixture was re-charged with additional portions of t-Bu₃P-HBF₄ligand (22.8 mg, 0.0788 mmol) and Pd(OAc)₂ catalyst (8.8 mg, 0.0394mmol) and heated in the microwave (Biotage) at 160° C. for 2 h. Themixture was allowed to cool, diluted with EtOAc, and washed once withsaturated NaHCO_(3(aq)), once with brine, and dried (MgSO₄). Flashchromatography over SiO₂ (24 g) using 20-80% EtOAc-hexanes (gradientelution) afforded2-methoxy-8-(trifluoromethyl)-9H-pyrido[4′,3′:4,5]pyrrolo[2,3-d]pyrimidine(34 mg, 33%).

4-(2-Chloroethyl)morpholine (0.01 mL, 0.05 mmol), followed by Tsunoda'sreagent ((cyanomethylene)tributylphosphorane, 15 mg, 0.05 mmol) wereadded via syringe to a stirred solution of2-methoxy-8-(trifluoromethyl)-9H-pyrido[4′,3′:4,5]pyrrolo[2,3-d]pyrimidine(7 mg, 0.03 mmol) in PhMe (0.8 mL) under N₂. The mixture was heated at100° C. overnight with stirring, allowed to cool, and diluted withEtOAc. The mixture was washed once with water, once with brine, anddried (Na₂SO₄). Evaporation of the solvent and flash chromatography overSiO₂ (0.5×10 cm) in a Pasteur pipette using 60-100% EtOAc-hexanesafforded4-(2-(2-Methoxy-8-(trifluoromethyl)-9H-pyrido[4′,3′:4,5]pyrrolo[2,3-d]pyrimidin-9-yl)ethyl)morpholine(2.8 mg, 28%).

Characterization for4-(2-(2-Methoxy-8-(trifluoromethyl)-9H-pyrido[4′,3′:4,5]pyrrolo[2,3-d]pyrimidin-9-yl)ethyl)morpholine¹H NMR (CDCl₃, 400 MHz) δ 9.19 (s, 1H), 8.61 (d, 1H, J=4.8 Hz), 8.10 (d,1H, J=5.2 Hz), 4.74 (t, 2H, J=7.6 Hz), 4.15 (s, 3H), 3.63 (t, 4H, J=4.8Hz), 2.75 (t, 2H, J=7.6 Hz), 2.57 (t, 4H, J=4.4 Hz). LCMS m/z 382.2([M+H]⁺, C₁₇H₁₉F₃N₅O₂ requires 382.2).

Example 64-(2-(3-Fluoro-2-methoxy-8-(trifluoromethyl)-9H-pyrrolo[2,3-b:5,4-c′]dipyridin-9-yl)ethyl)morpholinehydrochloride salt

Selectfluor (192 mg, 0.542 mmol) was added, in one portion, to a stirredsolution of2-methoxy-8-(trifluoromethyl)-9H-pyrrolo[2,3-b:5,4-c′]dipyridine (96.6mg, 0.362 mmol) in MeCN (3 mL). The flask was flushed with N₂ and heatedto 65 C, with stirring, for 2 days. The mixture was then diluted withEtOAc and washed once with dilute NaCl_((aq)), once with brine, dried(Na₂SO₄), and evaporated. The residue was filtered through a plug ofSiO₂ (2×4 cm), using 30% EtOAc-hexanes, to afford a mixture of2-methoxy-8-(trifluoromethyl)-9H-pyrrolo[2,3-b:5,4-c′]dipyridine/3-fluoro-2-methoxy-8-(trifluoromethyl)-9H-pyrrolo[2,3-b:5,4-c′]dipyridine(1:2, 75 mg, 48% based on conversion). The2-methoxy-8-(trifluoromethyl)-9H-pyrrolo[2,3-b:5,4-c′]dipyridine/3-fluoro-2-methoxy-8-(trifluoromethyl)-9H-pyrrolo[2,3-b:5,4-c′]dipyridine(1:2) mixture was purified by reverse-phase HPLC (Puri-Flash system,using Phenomenex Synergi 10u MAX-RP 80A 50×50 mm 10 micron column and10-95% MeCN-water containing 0.1% formic acid gradient elution) toafford a2-methoxy-8-(trifluoromethyl)-9H-pyrrolo[2,3-b:5,4-c′]dipyridine/3-fluoro-2-methoxy-8-(trifluoromethyl)-9H-pyrrolo[2,3-b:5,4-c′]dipyridine(3:17) mixture (19.1 mg), which was used in the next step, and anotherfraction consisting of a2-methoxy-8-(trifluoromethyl)-9H-pyrrolo[2,3-b:5,4-c′]dipyridine/3-fluoro-2-methoxy-8-(trifluoromethyl)-9H-pyrrolo[2,3-b:5,4-c′]dipyridine(7:3) mixture (10.4 mg).

A flask was charged2-methoxy-8-(trifluoromethyl)-9H-pyrrolo[2,3-b:5,4-c′]dipyridine/3-fluoro-2-methoxy-8-(trifluoromethyl)-9H-pyrrolo[2,3-b:5,4-c′]dipyridine(3:17) mixture (19 mg, 0.066 mmol) from the above experiment,4-(2-chloroethyl)morpholine hydrochloride salt (25 mg, 0.13 mmol), andTBAI (5 mg, 0.01 mmol). The flask was flushed with N₂, and DMF wasintroduced via syringe, with stirring. NaH (60% oil dispersion, 16 mg,0.40 mmol) was added and stirring was continued under a stream of N₂ for5 min before the N₂ exit needle was removed, and the mixture was heatedto 60° C., with stirring, overnight. The next day, the mixture wasdiluted with EtOAc and washed twice with water, once with brine, dried(Na₂SO₄), and evaporated. The residue was crystallized fromCH₂Cl₂-hexanes to afford partially pure4-(2-(3-Fluoro-2-methoxy-8-(trifluoromethyl)-9H-pyrrolo[2,3-b:5,4-c′]dipyridin-9-yl)ethyl)morpholine(12 mg). The mixture was further purified using silica chromatographyusing 30-80% EtOAc-hexanes and then crystallized again fromCH₂Cl₂-hexanes to afford compound4-(2-(3-fluoro-2-methoxy-8-(trifluoromethyl)-9H-pyrrolo[2,3-b:5,4-c′]dipyridin-9-yl)ethyl)morpholine(9 mg).

Characterization for4-(2-(3-fluoro-2-methoxy-8-(trifluoromethyl)-9H-pyrrolo[2,3-b:5,4-c′]dipyridin-9-yl)ethyl)morpholine:¹H NMR (CDCl₃, 400 MHz) δ 8.49 (d, 1H, J=5.2 Hz), 8.01 (d, 1H, J=9.6Hz), 7.97 (d, 1H, J=5.2 Hz), 4.76 (t, 2H, J=7.6 Hz), 4.18 (s, 3H), 3.69(t, 4H, J=4.4 Hz), 2.76 (t, 2H, J=7.6 Hz), 2.60 (t, 4H, J=4.4 Hz).

HCl (0.2 M in Et₂O, 0.22 mL, 0.044 mmol) was added via syringe, at afast drop-wise rate, to a stirred solution of4-(2-(3-fluoro-2-methoxy-8-(trifluoromethyl)-9H-pyrrolo[2,3-b:5,4-c′]dipyridin-9-yl)ethyl)morpholine(9mg) in CH₂Cl₂ (0.8 mL). After stirring for 5 min at room temperature,the volatiles were removed in-vacuo and the resulting solid was washedonce with a small volume of 1:1 Et₂O-hexanes, to remove grease. The saltwas then suspended in water (ca. 2 mL), with the aid of sonication,frozen, and lyophilized to afford4-(2-(3-fluoro-2-methoxy-8-(trifluoromethyl)-9H-pyrrolo[2,3-b:5,4-c′]dipyridin-9-yl)ethyl)morpholinehydrochloride salt (9 mg, quantitative).

Characterization for4-(2-(3-fluoro-2-methoxy-8-(trifluoromethyl)-9H-pyrrolo[2,3-b:5,4-c′]dipyridin-9-yl)ethyl)morpholinehydrochloride salt: ¹H NMR (DMSO-d₆, 400 MHz) δ 11.04 (s, 1H), 8.76 (d,1H, J=10.4 Hz), 8.54 (d, 1H, J=5.2 Hz), 8.44 (d, 1H, J=4.8 Hz), 4.95 (m,2H), 4.19 (s, 3H), 4.03 (d, 2H, J=10.8 Hz), 3.79 (m, 2H), 3.65 (d, 2H,J=10.4 Hz), 3.48 (m, 2H), 3.24 (m, 2H). LCMS m/z 399.2 ([M+H]⁺,C₁₈H₁₉F₄N₄O₂ requires 399.2).

Example 7 Modulation of Sclerostin/Wnt Activity

Compounds synthesized in accordance with the methods of Examples 1-6were assayed for their ability to restore Wnt signaling in the presenceof sclerostin consistent with a known sclerostin antagonist, sclerostinMab. See, Ellies et al., J Bone Miner Res 21:1738-1749 (2006). As shownin Table 1 below, sclerostin antagonized Wnt3a signaling in humanembryonic cells. The addition of a known sclerostin antagonist inhibitedsclerostin inhibition of Wnt3a signaling, thus restoring Wnt3a signalingin the cell (IC100 at 10 μM) (data not shown). The compounds of Examples1-6 also inhibited sclerostin inhibition of Wnt3a signaling and restoredWnt3a signaling in the cell.

Example 8 Bone Formation Assays

Mineralization (crystalline calcium phosphate formation) represents anin vitro model of bone formation. Using an assay in which the amount ofmineralization is quantified by measuring total calcium aftersolubilization of deposited crystalline calcium phosphate, sclerostinwas previously shown to inhibit mineralization in MC3T3-E1 (mousecalvarial) osteoblast cells. Li et al., J Bone Miner Res 24:578-588(2008). Following the protocol described in Li et al., Compounds wereassayed for their ability to rescue the inhibition of mineralization bysclerostin in MC3T3 osteoblast cells. Sclerostin treatment aloneresulted in a significant decrease in mineralization, as measured by thecalcium concentration (Table 1 and data not shown). Addition of acompound of Examples 1-6 neutralized sclerostin-mediated inhibition ofmineralization, as reflected by the increase in calcium concentration.

Example 9 Metabolic Stability

Compounds of the present invention (0.1 μM) were incubated withmicrosomes at 37° C. for a total of 60 minutes. The reaction containedpooled human liver microsomal protein (0.1 mg/mL) in potassium phosphatebuffer with NADPH. At the indicated time points (0, 5, 15, 30 and 60minutes). Samples were analyzed by LC/MS/MS and remaining parent drugwas calculated using Microsoft Excel (2007). Obach R S, Drug MetabDispos. 27(11):1350-1359 (1999).

TABLE 1 Compound activity on modulating sclerostin/Wnt activity,sclerostin inhibition of mineralization, and metabolic stability.Sclerostin Inhibition Sclerostin Inhibition Assay; of Mineralization;improvement over improvement over Metabolic Example sclerostin alonesclerostin alone Stability Sclerostin − − − protein 1 + + ++ 2 − − ++ 3++ ++ ++ 4 ++ ++ ++ 5 ++ ++ ++ 6 ++ ++ ++ − indicates no improvementover sclerostin protein alone + indicates an IC100 > 10 μM ++ indicatesan IC100 < 10 μM + indicates a stability of < 1x ++ indicates astability > 1x

Although the foregoing invention has been described in some detail byway of illustration and example for purposes of clarity ofunderstanding, one of skill in the art will appreciate that certainchanges and modifications can be practiced within the scope of theappended claims. In addition, each reference provided herein isincorporated by reference in its entirety to the same extent as if eachreference was individually incorporated by reference.

What is claimed is:
 1. A compound according to Formula I:

or a salt, hydrate, prodrug, or isomer thereof, wherein X is selectedfrom CR^(3b) and N, wherein N is optionally oxidized to thecorresponding N-oxide; Y is selected from CR^(3c) and N, wherein N isoptionally oxidized to the corresponding N-oxide; Z is selected fromCR^(3d) and N, wherein N is optionally oxidized to the correspondingN-oxide, provided that at least one of X, Y, and Z is N or thecorresponding N-oxide; A is

R^(N) is selected from the group consisting of heterocyclyl andheteroaryl, wherein the heterocyclyl moiety is selected from monocyclic,fused bicyclic, and bridged cyclic, the monocyclic heterocyclylcomprising from 4 to 7 ring members, the fused bicyclic and bridgedbicyclic heterocyclyl comprising from 7 to 10 ring members, eachheterocyclyl moiety having from 1 to 3 heteroatoms as ring membersselected from N, O, and S, wherein each heterocyclyl moiety comprises atleast one nitrogen atom as a ring member and is optionally substitutedwith from 1 to 3R⁶ moieties, the heteroaryl moiety comprises from 5 to10 ring members, wherein at least one ring member is a nitrogen atom andis optionally substituted with from 1 to 3R⁶ moieties, each R², R^(3b),R^(3c) and R^(3d) is independently selected from the group consisting ofH, halogen, C₁₋₆ alkyl, C₁₋₆ haloalkyl, C₂₋₆ alkenyl, C₂₋₆ alkynyl, C₁₋₆alkoxy, C₁₋₆ haloalkoxy, C₁₋₆ alkyl-OH, —O—C₁₋₆ alkyl-OH, C₃₋₆cycloalkyl-C₁₋₄alkoxy, and —OH; R⁶ is selected from the group consistingof —OH, C₁₋₃ alkyl, C₁₋₃ alkyl-OH, —O—C₁₋₃ alkyl, C₃₋₄heteroalkyl, C₁₋₃haloalkyl, —O—C₁₋₃ haloalkyl, halogen, and oxo.
 2. The compoundaccording to claim 1, having the Formula Ia, Ib, Ic, or Id:


3. The compound of claim 1, wherein R² is selected from the groupconsisting of H, halogen, C₁₋₆ alkyl, C₁₋₆ haloalkyl, C₁₋₆ alkoxy, andC₁₋₆ haloalkoxy.
 4. The compound of claim 1, wherein R² is selected fromthe group consisting of halogen, C₁₋₆ alkyl, C₁₋₆ haloalkyl, and C₁₋₆alkoxy.
 5. The compound of claim 4, wherein R² is C₁₋₆alkyl or C₁₋₆haloalkyl.
 6. The compound of claim 5, wherein R² is CH₃ or CF₃.
 7. Thecompound of claim 6, wherein R² is CH₃.
 8. The compound of claim 6,wherein R² is CF₃.
 9. The compound of claim 1, wherein each R^(3b),R^(3c) and R^(3d), when present, is independently selected from thegroup consisting of H, halogen, C₁₋₆ alkyl, C₁₋₆ haloalkyl, C₁₋₆ alkoxy,C₁₋₆ haloalkoxy.
 10. The compound of claim 9, wherein each R^(3b),R^(3c) and R^(3d), when present, is independently selected from thegroup consisting of H, halogen, and C₁₋₆ alkoxy.
 11. The compound ofclaim 10, wherein each R^(3b), R^(3c) and R^(3d), when present, isindependently selected from the group consisting of H, F, and methoxy.12. The compound of claim 1, wherein R^(3c), when present, is methoxy.13. The compound of claim 1, wherein R^(N) is heterocyclyl orheteroaryl.
 14. The compound of claim 13, wherein R^(N) is heterocyclyl.15. The compound of claim 14, wherein R^(N) is a monocyclicheterocyclyl.
 16. The compound of claim 13, wherein R^(N) is


17. The compound of claim 1, wherein R² is selected from the groupconsisting of H, C₁₋₆alkyl, and C₁₋₆ haloalkyl, R^(3c), if present, is Hor C₁₋₆ alkoxy; R^(3b) or R^(3d), if present, is H or halogen; and R^(N)is heterocyclyl or heteroaryl.
 18. The compound of claim 17, wherein R²is H or C₁₋₆ haloalkyl; R^(3c), if present, is C₁₋₆ alkoxy; R^(3b) orR^(3d), if present, is H or halogen; and R^(N) is


19. The compound of claim 2, wherein R² is C₁₋₆ alkyl or C₁₋₆ haloalkyl;R^(3b), if present, is H or halogen; R^(3c) is C₁₋₆ alkoxy; and R^(N) isheterocyclyl or heteroaryl.
 20. The compound of claim 19, wherein R² isC₁₋₆ haloalkyl; R^(3b), if present, is H or halogen; R^(3c) is C₁₋₆alkoxy; and R^(N) is


21. The compound of claim 20, wherein R² is CF₃; and R^(3c) is methoxy.22. The compound of claim 1, selected from the group consisting of

or salts, hydrates, or prodrugs thereof.
 23. A formate salt of acompound of claim
 1. 24. A sulfate salt of a compound of claim
 1. 25. Acitrate salt of a compound of claim
 1. 26. A hydrochloride salt of acompound of claim
 1. 27. A prodrug of a compound of claim
 1. 28. Apharmaceutical composition comprising a compound of claim 1 and apharmaceutically acceptable excipient.
 29. A method of promoting boneformation a subject in need thereof, comprising administering to thesubject a therapeutically effective of a compound of claim 1, therebypromoting bone formation in the subject.
 30. The method of claim 29,wherein the bone formation is promoted at a surgical site of injury orlocalized condition.
 31. The method of claim 30, wherein the boneformation is promoted at a surgical site selected from the groupconsisting of a bone fracture and weakened bone.
 32. The method of claim30, wherein the subject is in need of a spinal fusion, arthrodesis or anorthopedic or periodontal synthetic bone graft or implant.
 33. Themethod of claim 29, wherein the bone formation is systemic.
 34. Themethod of claim 29, wherein the subject has a low bone mass/densitycondition, a bone fracture, or periodontal disease.
 35. The method ofclaim 34, wherein the low bone mass condition is selected fromosteoporosis, osteopenia, osteogenesis imperfecta (OI),osteoporosis-pseudoglioma syndrome (OPPG), and secondary low bonecondition.
 36. The method of claim 35, wherein the low bone masscondition is selected from the group consisting of osteoporosis,osteopenia, and osteoporosis-pseudoglioma syndrome (OPPG).
 37. Themethod of claim 29, further comprising administering to the subject anosteoconductive matrix.
 38. The method of claim 37, wherein theosteoconductive matrix comprises an osteoinductive agent selected fromthe group consisting of bone allograft, bone autograft, and periodontalligament cells.
 39. The method of claim 37, wherein the osteoconductivematrix comprises a calcium salt, calcium sulfate, calcium phosphate, acalcium phosphate cement, hydroxyapatite, coralline based hydroyxapatite(HA), dicalcium phosphate, tricalcium phosphate (TCP), calciumcarbonate, collagen, plaster of Paris, phosphophoryn, a borosilicate, abiocompatible ceramic, a calcium phosphate ceramic, demineralized bonematrix, biphasic calcium phosphate, biocomposite, tantalum, titanium,polytetrafluoroethylene, sulfate salt, hydrogel, bioglass, orcombinations thereof.
 40. The method of claim 37, wherein theosteoconductive matrix comprises a calcium salt, calcium sulfate,calcium phosphate, a calcium phosphate cement, hydroxyapatite, corallinebased hydroyxapatite (HA), dicalcium phosphate, tricalcium phosphate(TCP), calcium carbonate, collagen, plaster of Paris, phosphophoryn, aborosilicate, a biocompatible ceramic, a calcium phosphate ceramic,demineralized bone matrix, biphasic calcium phosphate, biocomposite,tantalum, titanium, polytetrafluoroethylene, sulfate salt, or hydrogel.41. The method of claim 29, wherein the compound is administeredsequentially or in combination with an antiresorptive drug.
 42. Themethod of claim 41, wherein the compound is administered to a patientwho is being treated with the antiresorptive drug or has previously beentreated with the antiresorptive drug.
 43. The method of claim 41,wherein the antiresorptive drug is selected from the group consisting ofdenosumab, prolia, a RankL inhibitor, a bisphosphonate, a selectiveestrogen receptor modulator (SERM), calcitonin, a calcitonin analog,Vitamin D, a Vitamin D analog, and a cathepsin K inhibitor.
 44. Themethod of claim 41, wherein the antiresorptive drug is denosumab. 45.The method of claim 41, wherein the antiresorptive drug is administeredsystemically.
 46. The method of claim 41, wherein the antiresorptivedrug is administered locally.
 47. The method of claim 29, furthercomprising administering an anabolic agent.
 48. A medical devicecomprising a structural support, wherein an implantable portion of thestructural support is adapted to be permanently implanted within asubject, wherein the implantable portion is attached to a bone, thestructural support bearing at least a partial external coatingcomprising a compound of claims
 1. 49. A method of treating bone loss ina subject in need thereof, comprising administering to the subject atherapeutically effective of a compound of claim 1 in series or incombination with an antiresorptive agent, thereby treating bone loss ina subject.